Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ¨ No x

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of the Registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ¨ No x

As of April 30, 2014, the registrant had 18,192,534 shares of common stock, par value $0.001, outstanding.

	March 31,			December 31,
	2014			2013
Assets
Current assets
Cash and cash equivalents	$	59,550		$	13,521
Accounts receivable, net of allowances of $3,417 and $3,390 at March 31, 2014 and December 31, 2013, respectively		18,084			10,231
Inventories, net of allowances of $110 and $100 at March 31, 2014 and December 31, 2013, respectively		4,651			4,248
Deferred cost of rental revenue		283			289
Income tax receivable		—			87
Deferred tax asset-current		3,923			3,923
Prepaid expenses and other current assets		959			531
Total current assets		87,450			32,830
Property and equipment
Rental equipment, net of allowances of $282 and $156 at March 31, 2014 and December 31, 2013, respectively		39,832			37,573
Manufacturing equipment and tooling		2,584			2,551
Computer equipment and software		3,228			2,973
Furniture and equipment		603			601
Leasehold improvements		888			887
Construction in process		971			1,093
Total property and equipment		48,106			45,678
Less accumulated depreciation		(18,282	)		(15,956	)
Property and equipment, net		29,824			29,722
Intangible assets, net		345			215
Deferred tax asset - noncurrent		17,807			17,865
Other assets		80			1,765
Total assets	$	135,506		$	82,397

	March 31,			December 31,
	2014			2013
Liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)
Current liabilities
Accounts payable and accrued expenses	$	10,411		$	9,219
Accrued payroll		3,829			2,898
Current portion of long-term debt		5,038			5,258
Warranty reserve		490			420
Deferred revenue		1,716			1,487
Income tax payable		432			—
Total current liabilities		21,916			19,282
Long-term liabilities
Warranty reserve-noncurrent		431			389
Preferred stock warrant liability		—			260
Deferred revenue-noncurrent		1,104			776
Long-term debt, net of current portion		4,151			5,391
Total liabilities		27,602			26,098
Commitments and contingencies (Note 5)
Redeemable convertible preferred stock
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized; 0 and 9,541,631 shares issued and outstanding; liquidation preference of $0 and $136,660 at March 31, 2014 and December 31, 2013, respectively		—			118,671
Stockholders' equity (deficit)
Preferred stock, $0.001 par value per share; 100,000 shares authorized; 0 and 66,666 shares issued and outstanding; liquidation preference of $0 and $250 at March 31, 2014 and December 31, 2013, respectively		—			247
Common stock, $0.001 par value per share; 60,000,000 shares authorized for both periods; 18,151,551 and 280,974 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively		18			1
Additional paid-in-capital		170,517			—
Accumulated deficit		(62,631	)		(62,620	)
Total stockholders' equity (deficit)		107,904			(62,372	)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$	135,506		$	82,397

	Three months ended March 31,
		2014			2013
Revenue
Sales revenue	$	14,857		$	8,895
Rental revenue		8,776			6,852
Total revenue		23,633			15,747
Cost of revenue
Cost of sales revenue		7,541			5,191
Cost of rental revenue, including depreciation of $2,257 and $1,342, respectively		4,154			2,439
Total cost of revenue		11,695			7,630
Gross profit		11,938			8,117
Operating expenses
Research and development		635			503
Sales and marketing		5,705			4,147
General and administrative		4,049			2,834
Total operating expenses		10,389			7,484
Income from operations		1,549			633
Other income (expense)
Interest expense		(133	)		(104	)
Interest income		6			3
Decrease in fair value of preferred stock warrant liability		36			20
Other income		7			209
Total other income (expense), net		(84	)		128
Income before provision for income taxes		1,465			761
Provision for income taxes		577			31
Net income	$	888		$	730
Less deemed dividend on redeemable convertible preferred stock		(987	)		(1,723	)
Net loss attributable to common stockholders	$	(99	)	$	(993	)
Basic net loss per share attributable to common stockholders	$	(0.01	)	$	(3.65	)
Diluted net loss per share attributable to common stockholders	$	(0.01	)	$	(3.65	)
Weighted-average number of shares used in calculating loss per share
attributable to common stockholders - basic common		9,437,525			272,226
attributable to common stockholders - dilutive common		9,437,525			272,226

	Series B						Series C						Series D						Series E						Series F						Series G						Total
	redeemable						redeemable						redeemable						redeemable						redeemable						redeemable						redeemable
	convertible						convertible						convertible						convertible						convertible						convertible						convertible
	preferred stock						preferred stock						preferred stock						preferred stock						preferred stock						preferred stock						preferred
	Shares			Amount			Shares			Amount			Shares			Amount			Shares			Amount			Shares			Amount			Shares			Amount			stock
Balance, December 31, 2012		425,511		$	5,056			365,903		$	6,460			1,487,225		$	32,571			1,634,874		$	28,044			2,701,957		$	14,055			2,840,260		$	23,159		$	109,345
Warrants exercised		—			—			—			—			39,510			909			—			—			—			—			—			—			909
Deemed dividend on redeemable convertible preferred stock		—			—			—			—			—			—			—			268			—			376			—			1,079			1,723
Balance, March 31, 2013		425,511			5,056			365,903			6,460			1,526,735			33,480			1,634,874			28,312			2,701,957			14,431			2,840,260			24,238			111,977
Warrants exercised		—			—			—			—			46,391			1,139			—			—			—			—			—			—			1,139
Deemed dividend on redeemable convertible preferred stock		—			—			—			—			—			—			—			818			—			1,189			—			3,548			5,555
Balance, December 31, 2013		425,511			5,056			365,903			6,460			1,573,126			34,619			1,634,874			29,130			2,701,957			15,620			2,840,260			27,786			118,671
Warrants exercised		—			—			11,094			279			11,415			314			—			—			—			—			—			—			593
Deemed dividend on redeemable convertible preferred stock		—			—			—			—			—			—			—			139			—			207			—			641			987
Conversion of preferred stock to common stock in connection with initial public offering		(425,511	)		(5,056	)		(376,997	)		(6,739	)		(1,584,541	)		(34,933	)		(1,634,874	)		(29,269	)		(2,701,957	)		(15,827	)		(2,840,260	)		(28,427	)		(120,251	)
Balance, March 31, 2014		—		$	—			—		$	—			—		$	—			—		$	—			—		$	—			—		$	—		$	—

	Series A
	convertible										Additional						Total
	preferred stock						Common stock				paid-in			Accumulated			stockholders'
	Shares			Amount			Shares		Amount		capital			deficit			equity (deficit)
Balance, December 31, 2012		66,666		$	247			272,096	$	1	$	—		$	(81,018	)	$	(80,770	)
Stock-based compensation		—			—			—		—		24			—			24
Stock options exercised		—			—			222		—		1			—			1
Deemed dividend on redeemable convertible preferred stock		—			—			—		—		(25	)		(1,698	)		(1,723	)
Net income		—			—			—		—		—			730			730
Balance, March 31, 2013		66,666			247			272,318		1		—			(81,986	)		(81,738	)
Stock-based compensation		—			—			—		—		206			—			206
Stock options exercised		—			—			8,656		—		9			—			9
Warrants exercised - preferred		—			—			—		—		1			—			1
Deemed dividend on redeemable convertible preferred stock		—			—			—		—		(216	)		(5,339	)		(5,555	)
Net income		—			—			—		—		—			24,705			24,705
Balance, December 31, 2013		66,666			247			280,974		1		—			(62,620	)		(62,372	)
Stock-based compensation		—			—			—		—		43			88			131
Stock options exercised		—			—			8,975		—		11			—			11
Warrants exercised		—			—			72,544		—		22			—			22
Reclassification of warrant liability		—			—					—		76			—			76
Deemed dividend on redeemable convertible preferred stock		—			—			—		—		—			(987	)		(987	)
Conversion of preferred stock		(66,666	)		(247	)		14,259,647		14		120,484			—			120,251
Issuance of common stock in connection with initial public offering		—			—			3,529,411		3		49,881			—			49,884
Net income		—			—			—		—		—			888			888
Balance, March 31, 2014		—		$	—			18,151,551	$	18	$	170,517		$	(62,631	)	$	107,904

	Three months ended March 31,
	2014			2013
Cash flows from operating activities
Net income	$	888		$	730
Adjustments to reconcile net income to net cash provided by (used in) by operating activities:
Depreciation and amortization		2,658			1,661
Loss on rental units and other fixed assets		338			73
Provision for sales returns		948			362
Provision for doubtful accounts		196			482
Provision for rental revenue adjustments		1,672			1,159
Provision for inventory obsolescence		26			41
Stock-based compensation expense		131			24
Deferred tax assets		58			—
Decrease in fair value of preferred stock warrant liability		(36	)		(20	)
Changes in operating assets and liabilities
Accounts receivable		(10,669	)		(3,169	)
Inventories		(429	)		11
Deferred costs of rental revenue		6			(4	)
Prepaid expenses and other current assets		(428	)		(189	)
Accounts payable and accrued expenses		1,193			797
Accrued payroll		931			325
Warranty reserve		112			213
Deferred revenue		556			166
Income tax receivable		87			31
Income tax payable		432			—
Net cash provided by (used in) operating activities		(1,330	)		2,693
Cash flows from investing activities
Investment in intangible assets		(169	)		—
Production of rental equipment		(2,890	)		(3,162	)
Purchases of property and equipment		(169	)		(406	)
Refund of deposit		—			(1	)
Net cash used in investing activities		(3,228	)		(3,569	)
Cash flows from financing activities
Proceeds from redeemable convertible preferred stock warrants and common stock warrants exercised		467			865
Proceeds from stock options exercised		11			1
Proceeds from initial public offering		56,471			—
Costs associated with initial public offering		(4,902	)		—
Repayments of debt from investment in intangible assets		(53	)		(54	)
Repayment of borrowings		(1,407	)		(917	)
Net cash provided by (used in) financing activities		50,587			(105	)
Net increase (decrease) in cash and cash equivalents		46,029			(981	)
Cash and cash equivalents, beginning of year		13,521			15,112
Cash and cash equivalents, end of period	$	59,550		$	14,131
Supplemental disclosures of cash flow information
Cash paid during the period for interest		132			107
Cash paid during the period for income taxes		39			14
Non-cash transactions:
Deemed dividend on redeemable convertible preferred stock		987			1,723

The unaudited condensed financial statements have been prepared on the same basis as the annual audited financial statements and, in the opinion of management, reflect all adjustments necessary for a fair presentation for each of the periods presented. The results of operations for interim periods are not necessarily indicative of results to be achieved for full fiscal years or other interim periods.

Inogen, Inc. (Company or Inogen) was incorporated in Delaware on November 27, 2001. The Company is a medical technology company that develops, manufactures and markets innovative portable oxygen concentrators used for supplemental long-term oxygen therapy by patients with chronic obstructive pulmonary disease, or COPD, and other chronic respiratory conditions. The Company’s proprietary Inogen One systems are designed to address the quality-of-life and other shortcomings of the traditional oxygen therapy model, which Inogen calls the delivery model. Traditionally, oxygen therapy patients have relied upon stationary oxygen concentrator systems in the home in conjunction with regular deliveries of oxygen tanks or cylinders for ambulatory, or mobile, use, limiting their mobility and requiring them to plan activities outside of their homes around delivery schedules and a finite oxygen supply. The Company’s Inogens One systems concentrate the air around them to offer a single source of supplemental oxygen anytime, anywhere in devices weighing approximately five to seven pounds. Inogen’s products eliminate the need for oxygen deliveries, as well as regular use of a stationary concentrator, thereby improving patient quality-of-life and fostering patient mobility.

As contemplated by the Securities and Exchange Commission (SEC) under Rule 10-01 of Regulation S-X, the accompanying financial statements and related footnotes have been condensed and do not contain certain information that will be included in the Company’s annual financial statements and footnotes thereto. For further information refer to the financial statements and related footnotes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 filed with the SEC on April 1, 2014 (Annual Report).

The preparation of the Company’s condensed financial statements in accordance with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in these condensed financial statements and accompanying notes. Management bases these estimates and assumptions upon historical experience, existing and known circumstances, authoritative accounting pronouncements and other factors that management believes to be reasonable. Significant areas requiring the use of management estimates relate to inventory and rental asset valuations and write-downs, accounts receivable reserves and allowance for bad debts, returns and adjustments, stock compensation expense, impairment assessments, depreciation and amortization, income tax provision and uncertain tax positions, fair value of financial instruments, and fair values of acquired intangibles. Actual results could differ materially from these estimates.

Certain reclassifications have been made to prior years to conform to current period financial statement presentation with no effect on previously reported financial position, results of operations or cash flows.

The Company completed an initial public offering on February 20, 2014, and sold 3,529,411 shares to the public for $16.00 per share. In addition, to this offering the selling shareholders sold 982,302 shares for a combined total of 4,511,713 actively trading upon the completion of the offering. The Company netted approximately $49,668 after the underwriters discount and other associated expenses. The Company’s outstanding redeemable convertible preferred stock and non-redeemable preferred stock were all converted to common stock. As of March 31, 2014, the Company had 18,151,551 shares of common stock outstanding.

The Company generates revenue primarily from sales and rentals of its products. The Company’s products consist of its proprietary line of oxygen concentrators and related accessories. Other revenue, which is included in sales revenue on the Statement of Operations, comes from service contracts, extended warranty contracts and freight revenue for product shipments.

Revenue from product sales is recognized when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the price to the customer is fixed or determinable; and (4) collectability is reasonably assured. Revenue from product sales is recognized upon shipment of the product. Provisions for estimated returns and discounts are made at the time of shipment. Provisions for standard warranty obligations, which are included in cost of sales revenue on the Statements of Operations, are also provided for at the time of shipment.

Revenue from the sales of the Company’s services is recognized when no significant obligations remain undelivered and collection of the receivables is reasonably assured. The Company offers extended service contracts on its Inogen One concentrator line for periods ranging from 12 to 24 months after the end of the standard warranty period. Revenue from these extended service contracts is recognized in income on a straight-line basis over the contract period.

Accruals for estimated standard warranty expenses are made at the time that the associated revenue is recognized. The provisions for estimated returns, discounts and warranty obligations are made based on known claims and discount commitments and estimates of additional returns and warranty obligations based on historical data and future expectations. The Company had accrued $921 and $809 to provide for future warranty costs at March 31, 2014 and December 31, 2013, respectively.

The Company also offers a lifetime warranty for direct-to-consumer sales. For a fixed price, the Company agrees to provide a fully functional oxygen concentrator for the remaining life of the patient. Lifetime warranties are only offered to patients upon the initial sale of oxygen equipment by the Company and are non-transferable. Product sales with lifetime warranties are considered to be multiple element arrangements within the scope of the Accounting Standards Codification (ASC) 605-25—Revenue Recognition-Multiple-Element Arrangements.

There are two deliverables when product that includes a lifetime warranty is sold. The first deliverable is the oxygen concentrator equipment which comes with a standard warranty of three years. The second deliverable is the lifetime warranty that provides for a functional oxygen concentrator for the remaining lifetime of the patient. These two deliverables qualify as separate units of accounting.

The revenue is allocated to the two deliverables on a relative selling price method. The Company has vendor-specific objective evidence of selling price for the equipment. To determine the selling price of the lifetime warranty, the Company uses its best estimate of the selling price for that deliverable as the lifetime warranty is neither separately priced nor selling price is available through third-party evidence. To calculate the selling price associated with the lifetime warranties, management considered the profit margins of the overall business, the average estimated cost of lifetime warranties and the price of extended warranties. A significant estimate used to calculate the price and expense of lifetime warranties is the life expectancy of patients. Based on clinical studies, the Company estimates that 60% of patients will succumb to their disease within three years. Given the approximate mortality rate of 20% per year, the Company estimates on average all patients will succumb to their disease within five years. The Company has taken into consideration that when patients decide to buy an Inogen portable oxygen concentrator with a lifetime warranty, they typically have already been on oxygen for a period of time, which can have a large impact on their life expectancy from the time our product is deployed.

After applying the relative selling price method, revenue from equipment sales is recognized when all other revenue recognition criteria for product sales are met. Lifetime warranty revenue is recognized using the straight-line method during the fourth and fifth year after the delivery of the equipment which is the estimated usage period of the contract based on the average patient life expectancy.

Shipping and handling costs for sold products and rental assets, shipped to the Company’s customers are included on the Statements of Operations as part of cost of sales revenue and cost of rental revenue, respectively.

Revenue from the sales of used rental equipment is recognized upon delivery and when collectability is reasonably assured and other revenue recognition criteria are met. When a rental unit is sold, the related cost and accumulated depreciation are removed from their respective accounts, and any gains or losses are included in cost of sales revenue on the Statements of Operations..

The Company recognizes equipment rental revenue over the non-cancelable lease term, which is one month, less estimated adjustments, in accordance with ASC 840—Leases. The Company has separate contracts with each patient that are not subject to a master lease agreement with any payor. The Company evaluates the individual lease contracts at lease inception and the start of each monthly renewal period to determine if there is reasonable assurance that the bargain renewal option associated with the potential capped free rental period would be exercised. Historically, the exercise of such bargain renewal option is not reasonably assured at lease inception and most subsequent monthly lease renewal periods. If the Company determines that the reasonable assurance threshold for an individual patient is met at lease inception or at a monthly lease renewal period, such determination would impact the bargain renewal period for an individual lease. The Company would first consider the lease classification issue (sales-type lease or operating lease) and then appropriately recognize or defer rental revenue over the lease term, which may include a portion of the capped rental period. To date, the Company has not deferred any amounts associated with the capped rental period. Amounts related to the capped rental period have not been material in the periods presented.

The lease term begins on the date products are shipped to patients and are recorded at amounts estimated to be received under reimbursement arrangements with third-party payors, including Medicare, private payors, and Medicaid. Due to the nature of the industry and the reimbursement environment in which the Company operates, certain estimates are required to record net revenue and accounts receivable at their net realizable values. Inherent in these estimates is the risk that they will have to be revised or updated as additional information becomes available. Specifically, the complexity of many third-party billing arrangements and the uncertainty of reimbursement amounts for certain services from certain payors may result in adjustments to amounts originally recorded. Such adjustments are typically identified and recorded at the point of cash application, claim denial or account review. Accounts receivable are reduced by an allowance for doubtful accounts which provides for those accounts from which payment is not expected to be received, although product was delivered and revenue was earned. Upon determination that an account is uncollectible, it is written-off and charged to the allowance. Amounts billed but not earned due to the timing of the billing cycle are deferred and recognized in income on a straight-line basis over the monthly billing period. For example, if the first day of the billing period does not fall on the first of the month, then a portion of the monthly billing period will fall in the subsequent month and the related revenue and cost would be deferred based on the service days in the following month.

Rental revenue is recognized as earned, less estimated adjustments. Revenue not billed at the end of the period is reviewed for the likelihood of collections and accrued. The rental revenue stream is not guaranteed and payment will cease if the patient no longer needs oxygen or returns the equipment. Revenue recognized is at full estimated allowable amounts; transfers to secondary insurances or patient responsibility have no net effect on revenue. Rental revenue is earned for that month if the patient is on service on the first day of the 30-day period commencing on the recurring date of service for a particular claim, regardless if there is a change in condition or death after that date.

Included in rental revenue are unbilled amounts for which the revenue recognition criteria had been met as of period-end but were not yet billed to the payor. The estimate of unbilled rental revenue accrual is based on historical trends and estimates of future collectability.

The Company’s financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses, debt and warrants. The carrying values of cash and cash equivalents, accounts receivable and accounts payable and accrued expenses approximate fair values based on the short-term nature of these financial instruments.

The fair value of the Company’s debt approximates carrying value based on the Company’s current incremental borrowing rate for similar types of borrowing arrangements. Imputed interest associated with the Company’s non-interest bearing debt is insignificant and has been appropriate recognized in the respective periods.

The fair value of the Company’s preferred stock warrant liability was estimated using a Monte Carlo valuation model.

ASC 820—Fair Value Measurements and Disclosures, creates a single definition of fair value, establishes a framework for measuring fair value in U.S. GAAP and expands disclosures about fair value measurements. ASC 820 emphasizes that fair value is a market-based measurement, not an entity-specific measurement, and states that a fair value measurement should be determined based on assumptions that market participants would use in pricing the asset or liability. Assets and liabilities adjusted to fair value in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Level inputs, as defined by ASC 820, are as follows:

The following table summarizes fair value measurements by level at December 31, 2013 for the liabilities measured at fair value on a recurring basis:

The following table summarizes the fair value measurements using significant Level 3 inputs, and changes therein, for the three months ended March 31, 2014 and March 31, 2013:

The preferred stock warrant liability was marked to market at each reporting date and the fair value was estimated using a Monte Carlo valuation model, which takes into consideration the market values of comparable public companies, considering among other factors, the use of multiples of earnings, and adjusted to reflect the restrictions on the ability of the Company’s shares to trade in an active market.

Accounts receivable are customer obligations due under normal sales and rental terms. The Company performs credit evaluations of the customers’ financial condition and generally does not require collateral. The allowance for doubtful accounts is maintained at a level that, in management’s opinion, is adequate to absorb potential losses related to accounts receivable and is based upon the Company’s continuous evaluation of the collectability of outstanding balances. Management’s evaluation takes into consideration such factors as past bad debt experience, economic conditions and information about specific receivables. The Company’s evaluation also considers the age and composition of the outstanding amounts in determining their net realizable value.

The allowance is based on estimates, and ultimate losses may vary from current estimates. As adjustments to these estimates become necessary, they are reported in earnings in the periods that they become known. The allowance is increased by bad debt provisions charged to bad debt expense, net of recoveries, in operating expense and is reduced by direct write-offs, net of recoveries.

The Company does not allow returns from providers. Provision for sales returns applies to direct-to-consumer sales only. This reserve is calculated based on actual historical return rates under the Company’s 30-day return program and is applied to the sales revenue for direct-to-consumer sales for the last month of the quarter reported.

The Company also records an allowance for rental revenue adjustments and write-offs, which is recorded as a reduction of rental revenue and rental accounts receivable balances. These adjustments and write-offs result from contractual adjustments, audit adjustments, untimely claims filings or billings not paid due to another provider performing same or similar functions for the patient in the same period, all of which prevent billed revenue becoming realizable. The reserve is based on historical revenue adjustments as a percentage of rental revenue billed during the related period.

When recording the allowance for doubtful accounts, the bad debt expense account (general and administrative expense account) is charged, when recording allowance for sales returns, the sales returns account (contra sales revenue account) is charged, and when recording the allowance for adjustments, the rental revenue adjustments account (contra rental revenue account) is charged.

At March 31, 2014 and December 31, 2013, included in accounts receivable on the balance sheets were earned but unbilled receivables of $2,413 and $1,435, respectively.

Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash and cash equivalents and accounts receivable. At times, cash account balances may be in excess of the amounts insured by the Federal Deposit Insurance Corporation (FDIC). However, management believes the risk of loss to be minimal. The Company performs periodic evaluations of the relative credit standing of these institutions and has not experienced any losses on its cash and cash equivalents and short-term investments to date.

The Company sells its products to home medical equipment providers in the United States and in foreign countries on a credit basis. No single customer represented more than 10% of our total revenue for the three months ended March 31, 2014 and March 31, 2013.

The Company also rents products directly to patients, which resulted in a customer concentration relating to Medicare’s service reimbursement programs. Medicare’s service reimbursement programs (net of patient co-insurance obligations) accounted for 58.0% and 60.4% of rental revenue for the three months ended March 31, 2014 and March 31, 2013, respectively, and based on total revenue were 21.5% and 26.3% for the three months ended March 31, 2014 and March 31, 2013, respectively. Accounts receivable balances relating to Medicare’s service reimbursement programs amounted to $6,229 or 34.4% of total accounts receivable at March 31, 2014 as compared to $2,560, or 25.0% of total accounts receivable at December 31, 2013.

The Company currently purchases raw materials from a limited number of vendors, which resulted in a concentration of three major vendors. For the three months ended March 31, 2014, the Company’s three major vendors accounted for 18.8%, 17.8%, and 10.5%, respectively, of total raw material purchases. Accounts payable balances for the three major vendors were $1,416, $623, and $541, respectively, or 19.5%, 8.6%, and 7.4%, respectively, of total accounts payable at March 31, 2014.

For the three months ended March 31, 2013, the Company’s three major vendors accounted for 14.0%, 13.8% and 12.1%, respectively, of total raw material purchases for the three months ended March 31, 2013. The three major vendors supply the Company with raw materials used to manufacture the Company’s products. Accounts payable balances for the three major vendors were $1,268, $666, and $460, respectively, or 18.3%, 9.6%, and 6.7%, respectively, of total accounts payable at December 31, 2013.

A portion of revenue is earned from sales outside the United States. Non-U.S. revenue is denominated in U.S. dollars. A breakdown of the Company’s revenue from U.S. and non-U.S. sources for the three months ended March 31, 2014 and March 31, 2013 is as follows:

Inventories are stated at the lower of cost or market. Cost is determined using a standard cost method, including material, labor and manufacturing overhead, whereby the standard costs are updated at least quarterly to reflect approximate actual costs using the first-in, first out (FIFO) method and market represents the lower of replacement cost or estimated net realizable value. The Company records adjustments at least quarterly to inventory for potentially excess, obsolete, slow-moving or impaired items. Inventories consist of the following:

Property and equipment are stated at cost. Depreciation and amortization are calculated using the straight-line method over the assets estimated useful lives as follows:

Expenditures for additions, improvements and replacements are capitalized and depreciated to a salvage value of zero. Repair and maintenance costs are included in cost of revenue in the Statements of Operations. Repair and maintenance expense, which includes labor, parts and freight for rental equipment was $390 and $260 for the three months ended March 31, 2014 and March 31, 2013, respectively.

Included within property and equipment is construction in process relating to the design and engineering of tooling, jigs and other machinery. In addition, this item also includes computer software that has been purchased, but has not been completed the final configuration process adapted to the Company’s process and procedures for implementation into the Company’s systems. These items have not been placed in service, therefore no depreciation and amortization has been recognized in respective periods.

Depreciation and amortization expense related to property and equipment and rental equipment is summarized below for the three month ended March 31, 2014 and March 31, 2013, respectively.

Property and equipment and rental equipment with association accumulated depreciation is summarized below for March 31, 2014 and December 31, 2013, respectively.

	March 31,		December 31,
	2014		2013
Property and equipment
Rental equipment, net of allowance	$	39,832	$	37,573
Other property and equipment		8,274		8,105
Property and equipment		48,106		45,678

Accumulated depreciation
Rental equipment		14,508		12,545
Other property and equipment		3,774		3,411
Accumulated depreciation		18,282		15,956

Net property and equipment
Rental equipment		25,324		25,028
Other property and equipment		4,500		4,694
Property and equipment, net	$	29,824	$	29,722

The Company accounts for income taxes in accordance with ASC 740—Income Taxes. Under ASC 740, income taxes are recognized for the amount of taxes payable or refundable for the current three months and deferred tax liabilities and assets are recognized for the future tax consequences of transactions that have been recognized in the Company’s financial statements or tax returns. A valuation allowance is provided when it is more likely than not that some portion, or all, of the deferred tax asset will not be realized.

The Company accounts for uncertainties in income tax in accordance with ASC 740-10—Accounting for Uncertainty in Income Taxes. ASC 740-10 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This accounting standard also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition.

The Company recognizes interest and penalties on taxes, if any, within operations as income tax expense. No significant interest or penalties were recognized during the periods presented.

The Company accounts for its stock-based compensation in accordance with ASC 718, Compensation—Stock Compensation, which establishes accounting for share-based awards, exchanged for employee services and requires companies to expense the estimated fair value of these awards over the requisite employee service period. Stock–based compensation cost is determined at the grant date using the Black-Scholes option pricing model. The value of the award that is ultimately expected to vest is recognized as expense on a straight line basis over the employee’s requisite service period.

As part of the provisions of ASC 718, the Company is required to estimate potential forfeitures of stock grants and adjust compensation cost recorded accordingly. The estimate of forfeitures will be adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of stock compensation expense to be recognized in future periods.

The Company operates in only one business segment – manufacturing, sales, rental and marketing of oxygen concentrators.

On November 11, 2013, the Company’s board of directors and stockholders approved a 3:1 reverse stock split. This became effective as of November 12, 2013 and the effect of this event has been reflected in all of the share quantities and per share amounts throughout these financial statements. The shares of common stock retained a par value of $0.001.

Earnings per share (EPS) is computed in accordance with ASC 260, Earnings per Share, and is calculated using the weighted-average number of common shares outstanding during each period. Diluted EPS assumes the conversion, exercise or issuance of all potential common stock equivalents unless the effect is to reduce a loss or increase the income per share. For purposes of this calculation, common stock subject to repurchase by the Company, options and warrants are considered to be common stock equivalents and are only included in the calculation of diluted earnings per share when their effect is dilutive.

The shares used to compute basic and diluted net income per share represent the weighted-average common shares outstanding, reduced by the weighted-average unvested common shares subject to repurchase. Further, as the Company’s holders of redeemable convertible preferred stock have the right to participate in any dividend declared on the Company’s common stock, basic and diluted EPS are potentially subject to computation using the two-class method, under which the Company’s undistributed earnings are allocated amongst the holders of common and redeemable convertible preferred stock. However, as the Company recorded a net loss attributable to common stockholders for the three months ended March 31, 2014 and March 31, 2013, a presentation of EPS using the two class method was not necessary.

On February 20, 2014, the Company completed an initial public offering (IPO) of 4,411,763 shares of common stock at a price of $16.00 per share. The Company sold 3,529,411 shares of common stock and certain stockholders sold 882,352 shares of common stock. As of March 7, 2014 the underwriters elected to purchase 99,550 additional shares of common stock at the IPO price from the certain selling shareholders. All redeemable convertible preferred stock and non-redeemable preferred stock-outstanding as of the IPO automatically converted into 14,259,647 shares of common stock.

The computations of diluted net income applicable to common shareholders exclude redeemable convertible preferred stock, warrants and common stock options which were anti-dilutive for the three months ended March 31, 2014 and March 31, 2013.

During the year ended December 31, 2008, the Company acquired Comfort Life Medical, LLC (Comfort Life). The acquisition resulted in recording an intangible asset in the amount of $92 related to the Medicare license held by the acquired company. The Company amortizes this intangible asset over its estimated useful life of ten years. As of March 31, 2014 and March 31, 2013, there were no impairments recorded related to this intangible asset. On April 1, 2009, Comfort Life Medical, LLC merged with Inogen, Inc., and was simultaneously dissolved. During the year ended December 31, 2009, the Company was assigned four patents previously held as an exclusive license from Air Products & Chemicals (APC) in exchange for an increase in a long-term liability due to APC of $250. The acquisition of these patents resulted in an intangible asset of $250. During the year ended December 31, 2011, the Company purchased additional patents from APC for a total value of $650. The Company amortizes these intangible assets over an estimated useful life of five years. As of March 31, 2014 and March 31, 2013, there were no impairments recorded related to these intangible assets. The Company recalculated interest and amortization of the period based on adjusted asset and debt.

During the year ended December 31, 2011, the Company acquired Breathe Oxygen Services, LLC. The acquisition resulted in recording an intangible asset in the amount of $66 related to the Medicare license held by the acquired Company that allowed them to operate in the state of Tennessee as well as assets of the Company. On August 29, 2011, Breathe Oxygen Services, LLC merged with Inogen, Inc., and was simultaneously dissolved. The Company amortizes this intangible asset over its estimated useful life of ten years. During the three months ended March 31, 2014 and March 31, 2013, there were no impairments recorded related to this intangible asset. The Company also capitalizes costs incurred for the production of direct response advertising commercials and amortizes these intangible assets over a useful life of two years. During the three months ended March 31, 2014, the Company paid $169 for its patient setup video, website development and redesign and production of commercials.

Amortization expense for intangible assets for the three months ended March 31, 2014 and March 31, 2013 was $39 and $68, respectively.

The following tables represent the changes in net carrying values of the intangibles as of the respective dates:

On October 12, 2012, the Company entered into an amended and restated credit and term loan agreement with its current lenders whereby the existing balances and the payback terms were not changed. This transaction did not result in any debt extinguishment losses or gains. The Company did not incur or defer any financing cost directly related to the credit and term loan agreement. Due to the completion of the IPO during the term of this facility, a fee equal to 1% of the facility amount of $120, which was paid to the lenders in March of 2014, and was included in general and administrative expenses in the Company’s Statements of Operations for the current year.

The amended and restated credit and term loan agreement with the Company’s current lenders provides for new borrowings of up to $12,000, secured by substantially all of the Company’s assets. The amended and restated credit and term loan agreement provides for the existing term loan facility for rental assets amounting to up to $3,000 (Term Loan A), a term loan facility for rental assets amounting to up to $8,000 (Term Loan B), a new term loan facility for rental assets amounting to up to $12,000 (Term Loan C), and an accounts receivable revolving line of credit amounting to up to $1,000 based on 80% of eligible accounts receivable, as defined (AR Revolver).

Interest for all the term loans are payable monthly. Principal is payable monthly. Each term loan bears interest at the Base Rate, which is a rate equal to the applicable margin plus the greater of (i) the prime rate, (ii) the federal funds effective rate, as defined in the agreement, plus 1% and (iii) the daily adjusting LIBOR rate, plus 1%. The applicable margins for Term Loans A, B, and C are 1.25%, 2.5% and 2.25%, respectively.

The Term Loan A facility of $3,000 is presented net of principal payments that began in May 2011. The net balances of this term loan facility were $167 and $417 as of March 31, 2014 and December 31, 2013, respectively.

The Term Loan B facility for $8,000 is presented net of principal payments that began in May 2012. The net balances of this term loan facility were $3,111 and $3,778 as of March 31, 2014 and December 31, 2013, respectively.

The Term Loan C facility for $12,000 is presented net of principal payments that began November, 2013. The net balances were $5,166 and $5,666 as of March 31, 2014 and December 31, 2013, respectively. Payment of principal is payable monthly over a period of 36 months starting November 2013.

The AR Revolver expired on October 13, 2013, and was not renewed by the Company. There were no borrowings under the AR Revolver as of and during the three months ended March 31, 2014.

The interest rates were 4.5% for Term Loan A, 5.75% for Term Loan B, and 5.5% for Term Loan C at March 31, 2014 and December 31, 2013. As of March 31, 2014 and December 31, 2013, the Company was in compliance with all covenants of the amended and restated credit and term loan agreement.

As of March 31, 2014, the minimum aggregate payments due under non-cancelable debt are summarized as follows:

The Company leases its offices and certain equipment under operating leases that expire through December 2019. At March 31, 2014, the minimum aggregate payments due under non-cancelable leases are summarized as follows:

Rent expense of $207 and $198 was included in the accompanying Statements of Operations for the three months ended March 31, 2014 and March 31, 2013, respectively.

The following table identifies the changes in the Company’s aggregate product warranty liabilities for the three months ended March 31, 2014 and March 31, 2013:

The healthcare industry is subject to numerous laws and regulations of federal, state and local governments. These laws and regulations include, but are not necessarily limited to, matters such as licensure, accreditation, government healthcare program participation requirements, reimbursement for patient services, and Medicare and Medicaid fraud and abuse. Government activity has continued with respect to investigations and allegations concerning possible violations of fraud and abuse statutes and regulations by healthcare providers. Violations of these laws and regulations could result in expulsion from government healthcare programs together with the imposition of significant fines and penalties, as well as significant repayments for patient services previously billed.

The Company believes that it is in compliance in all material respects with applicable fraud and abuse regulations and other applicable government laws and regulations. Compliance with such laws and regulations can be subject to future government review and interpretation as well as regulatory actions unknown or unasserted at this time. The Company believes that is complies in all material respects with the provisions of those regulations that are applicable to the Company’s business.

The Health Insurance Portability and Accountability Act (HIPAA) assures health insurance portability, reduces healthcare fraud and abuse, guarantees security and privacy of health information, and enforces standards for health information. The Health Information Technology for Economic and Clinical Health Act (HITECH Act) imposes notification requirements of certain security breaches relating to protected health information. The Company may be subject to significant fines and penalties if found not to be compliant with the provisions outlined in the regulations.

On October 1, 2013, the Company entered into an Employment Agreement with the Chief Executive Officer (CEO) including considerations for salary, bonus awards, and severance and change of control benefits upon certain qualifying terminations up to a period of thirty-six months.

On October 1, 2013, the Company has entered into employment agreements with certain key employees including considerations for salary, bonus awards, and severance and change of control benefits upon certain qualifying terminations up to a period of twenty-four months.

On November 4, 2011, the Company filed a lawsuit in the United States District Court for the Central District of California against Inova Labs Inc., or Defendant, for infringement of two of our patents. The case, Inogen Inc. v. Inova Labs Inc., Case No. 8:11-cv-01692-JST-AN, or the Lawsuit, involves U.S. Patent Nos. 7,841,343, entitled “Systems and Methods For Delivering Therapeutic Gas to Patients”, or the ’343 patent, and 6,605,136 entitled “Pressure Swing Adsorption Process Operation And Optimization”, or the ’136 patent. Inogen alleged in the Lawsuit that certain of Defendant’s oxygen concentrators infringe various claims of the ’343 and ’136 patents. The Lawsuit seeks damages, injunctive relief, costs and attorney fees.

The Defendant has answered the complaint, denying infringement and asserting various sets of defenses including non-infringement, invalidity and unenforceability, patent misuse, unclean hands, laches and estoppel. The Defendant also filed counterclaims against us alleging patent invalidity, non-infringement and inequitable conduct. The Company denied the allegations in the Defendant’s counterclaims and has filed a motion to dismiss Defendant’s inequitable conduct counterclaim.

The Defendant filed a request with the U.S. Patent and Trademark Office seeking an inter partes reexamination of the ’343 and ’136 patents. The Defendant also filed a motion to stay the Lawsuit pending outcome of the reexamination. On March 20, 2012, the Court granted the Defendant’s motion to stay the Lawsuit pending outcome of the reexamination and also granted Inogen’s motion to dismiss the Defendant’s inequitable conduct counterclaim.

The Company is party to various legal proceedings arising in the normal course of business. The Company carries insurance, subject to deductibles under the specified policies, to protect against losses from certain types of legal claims. The Company does not anticipate that any of these proceedings will have a material impact on the Company.

The Company operates in multiple states. The statute of limitations has expired for all tax years prior to 2010 for federal and 2009 to 2010 for various state tax purposes. However, the net operating loss generated on the federal and state tax returns in prior years may be subject to adjustments by the federal and state tax authorities. The Company does not expect any material changes to unrecognized tax benefits in the in next 12 months, and has not incurred any tax related penalties or interest.

Income tax expense was $577, an effective tax rate of 39.4% for the three months ended March 31, 2014 compared to $31, an effective tax rate of 4.1% as of March 31, 2013. The variation in the tax rate year over year was primarily driven by the change in the Company’s deferred tax asset valuation allowance. As of March 31, 2013, the Company maintained a full valuation allowance against its federal and state deferred tax assets which significantly reduced the Company’s effective tax rate. In December of 2013, the Company evaluated its facts and circumstances and concluded that it was appropriate to release $22,909 of the valuation allowance which created a one-time tax benefit of $21,587 for the year ended December 31, 2013. Refer to the Company’s 2013 10-K filing for additional information regarding the deferred tax asset valuation allowance. Variations in the tax rate year-over-year was also due to an increase in permanent tax differences related to employee stock option expense.

The Company accounts for uncertainties in income tax in accordance with ASC 740-10—Accounting for Uncertainty in Income Taxes. ASC 740-10 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This Accounting Standard also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition.

A summary of the terms of the various types of redeemable convertible preferred stock at March 31, 2014, and December 31, 2013 is as follows:

Redeemable convertible preferred stock as of March 31, 2014
Series	B			C			D			E			F			G			Total
Shares authorized		500,000			400,000			1,700,000			1,700,000			2,800,000			2,900,000			10,000,000
Shares issued		425,511			376,997			1,584,541			1,634,874			2,701,957			2,840,260			9,564,140
Shares converted		(425,511	)		(376,997	)		(1,584,541	)		(1,634,874	)		(2,701,957	)		(2,840,260	)		(9,564,140	)
Shares outstanding		—			—			—			—			—			—			—

Redeemable convertible preferred stock as of December 31, 2013
Series	B			C			D			E			F			G			Total
Shares authorized		500,000			400,000			1,700,000			1,700,000			2,800,000			2,900,000			10,000,000
Shares issued		425,511			365,903			1,573,126			1,634,874			2,701,957			2,840,260			9,541,631
Par value	$	0.001		$	0.001		$	0.001		$	0.001		$	0.001		$	0.001
Conversion rate		1.45108			1.73014			1.87951			2.69244			1.0000			1.0000
Liquidation preference per share	$	11.880		$	17.580		$	21.900		$	19.224		$	7.140		$	14.083
Dividend rate		5	%		8	%		8	%		8	%		8	%		8	%

							July			October			February
							2005 to			2007 to			2010 to			March
Issue date	July 2003			June 2004			July 2007			February 2009			June 2010			2012

Redemption date	January 1,			January 1,			January 1,			January 1,			January 1,			January 1,
	2016			2016			2016			2016			2016			2016

A summary of the terms of non-redeemable convertible preferred stock at March 31, 2014 and December 31, 2013 is as follows:

All outstanding preferred stock automatically converted into common stock in connection with the closing of the IPO. At the closing of the IPO, 9,564,140 shares of redeemable convertible preferred stock and 66,666 shares of convertible preferred stock were automatically converted into 14,259,647 shares of common stock. Following the IPO, all warrants previously exercisable for preferred stock became exercisable for common stock. The previously reported warrant liability associated with the convertible warrants was applied to additional paid-in-capital.

The Company’s Series C preferred stock warrants expired in connection with the IPO. As of February 20, 2014, 2,756 Series C preferred stock warrants were forfeited and cancelled since they were not exercised prior to the IPO.

The board of directors approved and adopted a 2014 Equity Incentive Plan (2014 Plan) to become effective upon the close of the IPO that occurred on February 20, 2014. A total of 895,346 shares of common stock were reserved for issuance pursuant to the 2014 Plan. In addition, the shares reserved for issuance under the 2014 Plan also includes shares returned to the 2012 Plan as the result of expiration or termination of awards (provided that the maximum number of shares that may be added to the 2014 Plan pursuant to such previously granted awards under 2012 Plan is 2,328,569 shares). The number of shares available for issuance under the 2014 Plan will also include an annual increase on the first day of each fiscal year beginning in 2015, equal to the least of: (i) 895,346 shares; (ii) 4% of the outstanding shares of common stock as of the last day of the Company’s immediately preceding fiscal year; or (iii) such other amount as our board of directors may determine.

The Company had a 2012 Stock Incentive Plan (2012 Plan) under which the Company reserved 1,216,772 shares of common stock, to be issued in connection with stock options and other equity awards. The 2012 Plan provided for option grants at exercise prices not less than 100% of the fair value of common stock on the date of grant. As of February 14, 2014, the 2012 Plan was terminated and the 2014 Plan was created in its place.

Previously, the Company had a 2002 Stock Incentive Plan (2002 Plan), as amended. As of March 12, 2012, the 2002 Plan was terminated and the 2012 Plan was created in its place. On termination, the 2002 Plan had 1,424,540 shares of common stock outstanding. Any shares returned to the 2002 Plan as a result of expiration or termination of equity awards (up to 1,424,646 shares) are added to the 2012 Plan Share reserve.

Options typically expire ten years from the date of grant and vest over one to four year terms. Options have been granted to employees and consultants of the Company at the deemed fair market value, as determined by the board of directors, of the shares underlying the options at the date of grant.

There were no grants issued for the three months ended March 31, 2014. On April 1, 2014, the board approved grants totaling 632,694 shares to board members, executive officers and certain key employees with an exercise price of $16.62 per share.

The activity for stock options under the Plans for the three months ended March 31, 2014 is as follows:

Employee stock-based compensation expense for the three months ended March 31, 2014 and March 31, 2013 was calculated based on awards ultimately expected to vest and has been reduced for estimated forfeitures at a rate of 5.7% based on the Company’s historical option cancellations. ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

For the three months ended March 31, 2014 and March 31, 2013, stock-based compensation expense recognized under ASC 718, included in cost of sales, sales and marketing expense, general and administrative expense, and research and development expense, totaled $122 and $24, respectively.

The board approved and adopted an employee stock purchase plan (ESPP Plan) to be effective upon the completion of the initial public offering that occurred on February 20, 2014. The first offering period of this plan began on March 1, 2014. Enrollment dates will continue on the exercise date and will end on either the first trading date after September 1^st or March 1^st. There are two offering periods per year. The exercise price will be the lesser of 85% of the stock price on the enrollment date or the purchase date. The total number of shares available for issuance under the ESPP Plan is 179,069. The number of shares available for issuance under the ESPP Plan will be increased on the first day of each fiscal year beginning with the 2015 fiscal year equal to the least of (i) 179,069 shares of common stock, (ii) one-and-a-half percent (1.5%) of the outstanding shares of common stock on the last day of the immediately preceding fiscal year, or (iii) an amount determined by the Administrator. The Company recorded $9 of compensation expense for the three months ended March 31, 2014 associated with this Plan, which is included in the total ASC 718 stock-based compensation expense.

In connection with certain of its redeemable convertible preferred stock issuances, convertible debt financings, and other financing arrangements the Company had issued warrants for shares of its common stock and various issues of its redeemable convertible preferred stock. Such warrants related to its redeemable convertible preferred stock had been recorded as liabilities as a result of non-standard anti-dilution and redemption rights of the underlying stock and were carried at their estimated fair value using the Monte Carlo valuation model. As of February 14, 2014, the warrants were converted to common stock warrants with no anti-dilution features. The Company revalued the warrants as of the offering date, recorded a gain on the liability through the Statements of Operations, and subsequently reclassified the warrant liability to additional paid-in-capital.

The former Series E redeemable convertible preferred stock warrants convert directly to common stock equivalents with a conversion rate of $2.69244 for a total of 11,367 shares of common stock. The common stock warrants outstanding convert on a one-to-one basis of every warrant to common stock, therefore the 161,295 warrants outstanding as of March 31, 2014 could be exercised into a total of 172,662 shares of common stock.

The fair value of the preferred stock warrant liability was $0 and $260 at March 31, 2014 and December 31, 2013, respectively. During the three months ended March 31, 2014 and March 31, 2013, the Company recorded a gain of $36 and $20, respectively, on the change in fair value of the preferred stock warrants. The liability was reclassified to additional paid-in-capital as of February 14, 2014, and the warrants were converted to common stock warrants.

The compensation committee approved the right to grant 632,694 options to certain board members, executives and key personnel on March 19, 2014 from the 2014 Equity Incentive Plan. The options were granted and issued on April 1, 2014 with a closing stock price of $16.62 per share. In addition key executive officers and employees exercised stock options and were issued common stock of 50,983 shares with stock option prices ranging from $0.60 to $8.70 per share.

On April 22, 2014, the former redeemable convertible Series E preferred stock warrants, that were converted to common stock warrants as of February 14, 2014, were exercised via a cashless exercise and 8,650 shares of common stock was issued.

The Company had additional debt capacity on its Term Loan C facility that would have expired on April 11, 2014. The Company drew the remaining $6,000 in available funds on April 4, 2014. The additional debt was added to the original agreement, and principal will be payable monthly over the remaining period of thirty months of the term agreement which begins in May 2014.

Item 2: Management’s Discussion and Analysis of Financial Condition and Results of Operations

This report and the information incorporated by reference in this report contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, that concern matters that involve risks and uncertainties that could cause actual results to differ materially from those anticipated or projected in the forward-looking statements. These forward-looking statements are intended to qualify for the safe harbor from liability established by the Private Securities Litigation Reform Act of 1995. All statements other than statements of historical fact contained in this interim report, including statements regarding future events, our future financial performance, our future business strategy and the plans and objectives of management for future operations, are forward-looking statements. We have attempted to identify forward-looking statements by using words such as “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “project,” “plan,” “predict,” “should,” “will,” “would” and similar expressions, or the negative of these expressions, as they relate to us, our management and our industry.

We have based our forward-looking statements on our current expectations and projections about trends affecting our business and industry and other future events. Although we do not make forward-looking statements unless we believe we have a reasonable basis for doing so, we cannot guarantee their accuracy.

Some of the risks, uncertainties and assumptions that may cause actual results to differ from these forward-looking statements are described in Part II, Item 1A of this interim report in the section entitled “Risk Factors,” as well as in our other filings with the SEC. In addition, actual results may differ as a result of additional risks and uncertainties of which we are currently unaware or which we do not currently view as material to our business. We operate in a very competitive and rapidly changing environment. New risk factors emerge from time to time and we cannot predict all such risk factors, nor can we assess the impact of all such risk factors on our business or the extent to which any factor or combination of factors may cause actual results to differ materially from those contained in any forward-looking statements. As a result, actual results may differ materially from the results stated in or implied by our forward-looking statements. Given these risks and uncertainties, investors should not place undue reliance on forward-looking statements, which reflect our opinions only as of the date of this quarterly report, as a prediction of actual results.

You should read this report in its entirety, together with our Annual Report on Form 10-K for the year ended December 31, 2013, filed with the SEC on April 1, 2014 (Annual Report), and the documents that we file as exhibits to these reports and the documents that we incorporate by reference in these reports, with the understanding that our future results may be materially different from what we currently expect. We qualify all of our forward-looking statements by these cautionary statements and we expressly disclaim any intent or obligation to update any forward-looking statements after the date hereof to conform such statements to actual results or to changes in our opinions or expectations, except as required by applicable law or the rules of the NASDAQ Stock Market.

Unless otherwise specifically indicated, all amounts herein are expressed in thousands, except for share quantity, per share data, and unit counts. The following discussion of our financial condition and results of operations should be read together with our condensed financial statements and the accompanying notes to those statements included elsewhere in this document.

Our discussion and analysis of our financial condition and results of operations are based upon our financial statements which have been prepared in accordance with GAAP. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets and liabilities and related disclosure of contingent assets and liabilities, revenue and expenses at the date of the financial statements. Generally, we base our estimates on historical experience and on various other assumptions in accordance with GAAP that we believe to be reasonable under the circumstances. Actual results may differ from these estimates and such differences could be material to the financial position and results of operations.

There have been no material changes in our critical accounting policies and estimates in the preparation of our condensed financial statements during the three months ended March 31, 2014 compared to those disclosed in our Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the SEC on April 1, 2014.

We are a medical technology company that develops, manufactures and markets innovative portable oxygen concentrators used to deliver supplemental long-term oxygen therapy to patients suffering from chronic respiratory conditions. Traditionally, these patients have relied on stationary oxygen concentrator systems for use in the home and oxygen tanks or cylinders for mobile use. The tanks and cylinders must be delivered regularly and have a finite amount of oxygen, which limits patient mobility and requires patients to plan activities outside of their homes around delivery schedules. Additionally, patients must attach long, cumbersome tubing to their stationary concentrators simply to enable mobility within their homes. We refer to this traditional delivery approach as the delivery model. Our proprietary Inogen One systems are portable devices that concentrate the air around them to offer a single source of supplemental oxygen anytime, anywhere. Using our systems, patients can eliminate their dependence on stationary concentrators and tank and cylinder deliveries, thereby improving quality-of-life and fostering mobility.

We believe our direct-to-consumer strategy has been critical to driving patient adoption of our technology. All other portable oxygen concentrator manufacturers access patients through home medical equipment providers, which we believe are disincentivized to encourage portable oxygen concentrator adoption. In order to facilitate the regular delivery and pickup of oxygen tanks, home medical equipment providers have invested in geographically dispersed distribution infrastructures consisting of delivery vehicles, physical locations, and delivery personnel within each area. Because portable oxygen concentrator technology eliminates the need for physical distribution infrastructure but has higher initial equipment costs than oxygen tanks and cylinders, we believe converting to a portable oxygen concentrator model would require both significant restructuring and capital investment for home medical equipment providers. Our direct-to-consumer marketing strategy allows us to sidestep the home medical equipment channel, appeal to patients directly, and capture both the manufacturing and provider margin.

We believe our ability to capture this top-to-bottom margin, combined with our portable oxygen concentrator technology that eliminates the need for the costs associated with oxygen deliveries, gives us a cost structure advantage over our competitors using the delivery model. We derive a majority of our revenue from the sale and rental of our Inogen One systems and related accessories to patients, insurance carriers, home healthcare providers and distributors. We sell multiple configurations of our Inogen One systems with various batteries, accessories, warranties, power cords, and language settings. We also rent our products to Medicare beneficiaries and patients with other insurance coverage to support their oxygen needs as prescribed by a physician as part of a care plan. Our goal is to design, build and market oxygen solutions that redefine how oxygen therapy is delivered. To accomplish this goal and to grow our revenue, we intend to continue to:

We have been developing and refining the manufacturing of our Inogen One systems over the past nine years. While nearly all of our manufacturing and assembly processes were originally outsourced, assembly of the manifold, compressor, sieve bed and concentrator is now conducted in-house in order to improve quality control and reduce cost. Additionally, we use lean manufacturing practices to maximize manufacturing efficiency. We rely on third-party manufacturers to supply several components of our Inogen One systems. We typically enter into supply agreements for these components that specify quantity, quality requirements and delivery terms. In certain cases, these agreements can be terminated by either party upon relatively short notice. We have elected to source certain key components from single sources of supply, including our batteries, bearings, carry bags, motors, pistons, valves, and molded plastic components. While alternative sources of supply are readily available for these components, we believe that maintaining a single-source of supply allows us to control production costs and inventory levels, and to manage component quality.

Historically, we have generated a majority of our revenue from sales and rentals to customers in the United States. For the three months ended March 31, 2014 and 2013 approximately 18.8% and 20.5%, respectively, of our total revenue was from customers outside the United States, primarily in Europe. To date, all of our revenue has been denominated in United States dollars. We sell our products in 43 countries outside the United States through distributors or directly to large “house” accounts, which include gas companies and home oxygen providers. In this case, we sell to and bill the distributor or “house” accounts directly, leaving responsibility for the patient billing, support and clinical setup to the local provider.

Our total revenue increased $7.9 million to $23.6 million for the three months ended March 31, 2014 from $15.7 million for the three months ended March 31, 2013, primarily due to the growth in direct-to-consumer cash sales and business-to-business sales of our Inogen One systems and growth in rental revenue associated with an increase in the number of patients using Medicare or private payors to rent our products, partially offset by declining Medicare reimbursement rates. We generated Adjusted EBITDA of $4.3 million and $2.5 million for the three months ended March 31, 2014 and 2013, respectively. We generated net income before deemed dividend of $0.9 million and $0.7 million for the three months ended March 31, 2014 and March 31, 2013, respectively. As of March 31, 2014, our accumulated deficit was $62.6 million. The vast majority of our revenue consists of sales revenue and rental revenue.

The following describes the line items set forth in our Statements of Operations.

We classify our revenue in two main categories: sales revenue and rental revenue. There will be fluctuations in mix between business-to-business sales, direct-to-consumer sales, and rentals from period-to-period. We expect rental revenue should constitute a larger percentage of total revenue, which would increase our gross margins. In addition, we expect both the average selling price and the manufacturing cost of our products to decrease following the introduction of future generations of our Inogen One systems. Inogen One system selling prices and gross margins may fluctuate as we introduce new products and reduce our product costs. For example, the gross margin for our Inogen One G3 is higher than our Inogen One G2. Thus, to the extent our sales of our Inogen One G3 systems are higher than sales of our Inogen One G2 systems, our overall gross margins should improve and, conversely, to the extent our sales of our Inogen One G2 systems are higher than sales of our Inogen One G3 systems, our overall gross margins should decline.

Our sales revenue is derived from the sale of our Inogen One systems and related accessories to patients in the United States and to home healthcare providers, distributors and resellers worldwide. Sales revenue is classified into two areas: business-to-business sales and direct-to-consumer sales. For the three months ended March 31, 2014 and March 31, 2013, business-to-business sales as a percentage of sales revenue were 53.1% and 58.9%, respectively. Generally, our direct-to-consumer sales have higher margins than our business-to-business sales. We sold approximately 6,300 Inogen One systems in the first three months of 2014 compared to approximately 3,600 for the same period in 2013 across all sales channels. Management focuses on system sales as an indicator of current business success.

Our sales of used rental equipment revenue is included in sales revenue, and is derived from the sale of our Inogen One systems and related accessories to home healthcare providers and patients when the product has previously been sold or rented to another patient or business.

Other revenue included in sales revenue consists of service and freight revenue. Revenue from the sales of our services is recognized when no significant obligations remain undelivered and collection of the receivables is reasonably assured. We offer extended service contracts on our Inogen One concentrator line for periods ranging from 12 to 24 months after the end of the standard warranty period. Revenue from these extended service contracts is recognized in income on a straight-line basis over the contract period.

We also offer a lifetime warranty for direct-to-consumer sales. For a fixed price, we agree to provide a fully functional oxygen concentrator for the remaining life of the patient. Lifetime warranties are only offered to patients upon the initial sale of oxygen equipment by us, and are non-transferable. Product sales with lifetime warranties are considered to be multiple element arrangements within the scope of ASC 605-25.

There are two deliverables when a product that includes a lifetime warranty is sold. The first deliverable is the oxygen concentrator equipment which comes with a standard warranty of three years. The second deliverable is the lifetime warranty that provides for a functional oxygen concentrator for the remaining lifetime of the patient. These two deliverables qualify as separate units of accounting.

The revenue is allocated to the two deliverables on a relative selling price method. We have vendor-specific objective evidence of selling price for the equipment. To determine the selling price of the lifetime warranty, we use our best estimate of the selling price for that deliverable as the lifetime warranty is neither separately priced nor is a selling price available through third-party evidence. To calculate the selling price associated with the lifetime warranties, management considered the profit margins of the overall business, the average estimated cost of lifetime warranties and the price of extended warranties. A significant estimate used to calculate the price and expense of lifetime warranties is the life expectancy of patients. Based on clinical studies, we estimate that 60% of patients will succumb to their disease within three years. Given the approximate mortality rate of 20% per year, we estimate on average all patients will succumb to their disease within five years. We have taken into consideration that when patients decide to buy an Inogen portable oxygen concentrator with a lifetime warranty, they typically have already been on oxygen for a period of time, which can have a large impact on their life expectancy from the time our product is deployed.

Freight revenue consists of fees associated with the deployment of products internationally or domestically, when expedited freight options or minimum order quantities are not met. Freight revenue is a percentage markup of freight costs.

Our rental revenue is derived from the rental of our Inogen One systems to patients through reimbursement from Medicare, private payors and Medicaid, which typically also includes a patient responsibility component for patient co-insurance and deductibles. On average, our product rentals have higher gross margins than our product sales.

As of March 31, 2014, we had over 23,000 oxygen rental patients, an increase from approximately 15,400 oxygen rental patients as of March 31, 2013.

We manufacture our Inogen One product line in our Goleta, California and Richardson, Texas facilities. Our manufacturing process includes final assembly, testing, and packaging to customer specifications. Cost of sales revenue consists primarily of costs incurred in the production process, including costs of component materials, assembly labor and overhead, warranty, provisions for slow-moving and obsolete inventory and delivery costs for items sold. Cost of rental revenue consists primarily of depreciation expense and service costs for rental assets, including material, labor, freight, consumable disposables and logistics costs. We provide a three-year or lifetime warranty on Inogen One systems sold, and we establish a reserve for warranty repairs based on historical warranty repair costs incurred. Provisions for warranty obligations, which are included in cost of sales revenue, are provided for at the time of shipment. We expect the average unit costs of our Inogen One systems to decline in future periods as a result of our ongoing efforts to develop lower-cost Inogen One systems and to improve our manufacturing processes, reduced rental service costs and expected increases in production volume and yields.

As a result of bringing manufacturing and assembly largely in-house and our commitment to driving efficient manufacturing processes, we have reduced our overall system cost by 40% since 2009. We intend to continue to seek ways to reduce our cost of revenue through manufacturing and design improvements.

Research and development expenses consist primarily of personnel-related expenses, including salaries, benefits and stock-based compensation, allocated facility costs, laboratory supplies, consulting fees and related costs, costs associated with patent amortization costs, patent legal fees including defense costs and testing costs for new product launches. We have made substantial investments in research and development since our inception. Our research and development efforts have focused primarily on the tasks required to enhance our technologies and to support development and commercialization of new and existing products. We expect to have moderate increases in research and development expense over time.

Our sales and marketing expenses primarily support our direct-to-consumer strategy. Our sales and marketing expenses consist primarily of personnel-related expenses, including salaries, commissions, benefits, and stock-based compensation, for employees, and allocated facilities costs. They also include expenses for media and advertising, informational kits, public relations and other promotional and marketing activities, including travel and entertainment expenses, as well as customer service and clinical services. Sales and marketing expenses increased throughout 2013 primarily due to an increase in the sales force and the increasing number of rental patients and we expect a further increase in 2014 as we continue to increase sales and marketing activities.

General and administrative expenses consist primarily of personnel-related expenses, including salaries, benefits, and stock-based compensation for employees in our compliance, finance, medical billing, human resources, information technology, business development and general management functions, and allocated facilities costs. In addition, general and administrative expenses include professional services, such as legal, consulting and accounting services. We expect general and administrative expenses to increase in future periods as the number of administrative personnel grows and we continue to introduce new products, broaden our customer base and grow our business. We also expect legal, accounting, insurance and compliance costs to increase due to costs associated with being a public company.

Other income (expense), net consists primarily of interest expense related to our revolving credit and term loan agreement and interest income driven by the interest accruing on cash and cash equivalents and on past due customer balances. Other income (expense) also includes the change in valuation of warrant liability based on the Monte Carlo valuation model.

The increase in sales revenue for the three months ended March 31, 2014 compared to the three months ended March 31, 2013 was attributable to an increase in the number of systems sold as the adoption of portable oxygen concentrators improved. In addition, the increase in the number of systems sold resulted from an increase in direct-to-consumer sales in the United States due to increased sales and marketing efforts and an increase in business-to-business sales worldwide.

The increase in rental revenue for the three months ended March 31, 2014 compared to the three months ended March 31, 2013 was attributable to the increase in rental patients from approximately 15,400 as of March 31, 2013 to approximately 23,000 as of March 31, 2014. This increase was primarily due to additional marketing efforts, increased sales personnel and increased sales productivity improvements. The increase in rental revenue was partially offset by the reduced reimbursement rates resulting from competitive bidding. Round two of competitive bidding became effective in 91 Metropolitan Statistical Areas (MSAs) on July 1, 2013 and round one re-compete became effective in nine MSAs on January 1, 2014.

As expected, the growth in sales revenue was not impacted by the reduced reimbursement rates resulting from competitive bidding.

	Three months ended March 31,						Change 2014 vs. 2013
	2014			2013			$		%
Cost of sales revenue	$	7,541		$	5,191		$	2,350		45.3	%
Cost of rental revenue		4,154			2,439			1,715		70.3	%
Total cost of revenue	$	11,695		$	7,630		$	4,065		53.3	%

Gross profit - sales revenue	$	7,316		$	3,704		$	3,612		97.5	%
Gross profit - rental revenue		4,622			4,413			209		4.7	%
Total gross profit	$	11,938		$	8,117		$	3,821		47.1	%

Gross margin percentage - sales revenue		49.2	%		41.6	%
Gross margin percentage- rental revenue		52.7	%		64.4	%
Total gross margin percentage		50.5	%		51.5	%

The increase in cost of sales revenue was attributable to an increase in the number of systems sold, partially offset by reduced bill of material and labor and overhead costs for our products associated with better sourcing and increased volumes. The increase in cost of rental revenue was attributable to an increase of rental patients and related rental assets, depreciation and product exchange and logistics costs. Cost of rental revenue includes depreciation of our rental assets of $2.3 million for the three months ended March 31, 2014 versus $1.3 million for the three months ended March 31, 2013.

Gross margin is defined as revenue less costs of revenue divided by revenue. The overall gross margin decreased year-over-year mainly due to the gross margin decline in rental revenue partially offset by the increasing gross margin for the sales revenues. The rental revenue gross margin was 52.7% for the three months ended March 31, 2014 versus 64.4% for the three months ended March 31, 2013, due to lower rental reimbursement rates resulting from the implementation of round two and round one re-compete of competitive bidding that became effective July 1, 2013 and January 1, 2014, respectively. This was partially offset by a lower asset deployment costs per patient. The sales margins increased to 49.2% for the three months ended March 31, 2014 from 41.6% for the three months ended March 31, 2013. This increase in sales gross margin can be attributed to the increasing percentage of the Inogen One G3 product mix as compared to our Inogen One G2 and the continued shift towards direct-to-consumer sales revenue in our revenue mix and additional economies of scale of our servicing costs.

The increase in research and development expense was primarily attributable to personnel-related expenses as a result of increased headcount and patent and patent defense costs.

Research and development expenses were $0.6 million, or 2.7% of total revenue, for the three months ended March 31, 2014 compared to $0.5 million, or 3.2% of total revenue, for the three months ended March 31, 2013.

The increase in sales and marketing expense was primarily attributable to a $0.8 million increase in personnel-related expenses as a result of increased headcount to support the growth of our business, $0.4 million increase in media-related marketing costs and software licensing to continue to grow our rental patient base and consumer cash sales, $0.1 million increase in personnel-related expenses for customer service and clinical services to support our increased rental patient base, $0.1 million increase in sales incentives and giveaways, and $0.1 million increase in credit card processing fees due to higher sales.

Sales and marketing expenses were $5.7 million, or 24.1% of total revenue, for the three months ended March 31, 2014 compared to $4.1 million, or 26.3% of total revenue, for the three months ended March 31, 2013.

The increase in general and administrative expense was primarily attributable to a $0.7 million increase in personnel-related expenses as a result of increased a headcount in billing, finance, information technology and compliance to support the growth of our business. In addition, we incurred an increase of $0.1 million for higher audit and tax fees related to the filing of our first Annual Report on Form 10-K, $0.1 million for other costs associated with our reporting obligations as a public company, $0.1 million for a one-time fee to our lenders for the our initial public offering, $0.1 million in additional licenses and fees, and $0.1 million of increased depreciation expense.

Bad debt expense, expressed as a percentage of total revenue, was 0.8% and 3.1% for the three months ended March 31, 2014 and March 31, 2013, respectively. The decrease in bad debt as a percentage of total revenue was primarily the result of lower rental receivables that needed to be reserved against as well as an increase in direct-to-consumer sales within in our revenue mix. Payment for direct-to-consumer sales is required prior to shipment versus rental payments which have a longer collection cycle.

General and administrative expenses were $4.0 million, or 17.1% of total revenue, for the three months ended March 31, 2014 compared to $2.8 million, or 18.0% of total revenue, for the three months ended March 31, 2013.

The higher interest income in 2014 was associated with interest from the net proceeds generated from our initial public offering in February of 2014. The increase in interest expense in 2014 was driven by the increase in average outstanding debt balances under our revolving credit and term loan agreement compared to the prior year. Other income, net, in 2013 was primarily associated with investment income received in connection with the sale of our interest in our former product liability insurance company. This other income is not expected to recur in future periods.

The increase in income tax expense was primarily due to an increase in the effective tax rate of 3,525 basis points to 39.4% from 4.1%. The increase in the effective tax rate was largely driven by the change in the Company’s deferred tax asset valuation allowance. As of March 31, 2013, the Company maintained a full valuation allowance against its federal and state deferred tax assets which significantly reduced the Company’s effective tax rate. In December of 2013 the Company evaluated its facts and circumstances and concluded that it was appropriate to release $22.9 million of the valuation allowance which created a one-time tax benefit of $21.6 million. Also, variations in the tax rate year-over-year were due to an increase in permanent tax differences related to employee stock option expense.

There have been no material changes, outside of the ordinary course of business, in our outstanding contractual obligations from those disclosed within “Management’s Discussion and Analysis of Financial Condition and Results of Operations”, as contained in our Annual Report on Form 10-K filed with the SEC on April 1, 2014.

As of March 31, 2014, we had cash and cash equivalents of $59.6 million, which consisted of highly-liquid investments with an original maturity of three months or less. Since inception, we have financed our operations primarily through our sales and rental revenue, the sale of equity securities and, to a lesser extent, from borrowings. On February 20, 2014 we completed our initial public offering and received net proceeds after commissions and expenses of $49.7 million. As of March 31, 2014, we had $9.2 million secured debt outstanding including $8.4 million in bank financing and $0.8 million in patent licensing debt. Since inception, we have received net proceeds of $91.9 million from the issuance of redeemable convertible preferred stock. As of March 31, 2014, we had $6.0 million in available debt capacity under the term loan facility that was eligible to be drawn upon through April 11, 2014, and we drew upon the remaining availability on April 4, 2014. Our principal uses of cash are funding our capital expenditures including additional rental assets and debt service payments as described below.

We believe that our current cash and cash equivalents together with our short-term investments and available borrowings under our revolving credit and term loan agreement and the cash to be generated from expected product sales and rentals, will be sufficient to meet our projected operating and investing requirements for at least the next 12 months.

The following table shows a summary of our cash flows for the periods indicated:

We derive operating cash flows from cash collected from the sale of our products and services. These cash flows received are partially offset by our use of cash for operating expenses to support the growth of our business. Net income in each period has increased associated with increased sales, improving product mix and lower costs of revenues. In addition, operating expense leverage has increased as expenses have not grown as quickly as revenues due to improved operating efficiencies. The changes in cash related to operating assets and liabilities discussed below were primarily due to the following factors that occurred across all periods: an increase in cash used related to inventory to support our growth in revenue; an increase in cash used by accounts receivable resulting from growth in rental receivables which typically have a longer collection cycle; and an increase in cash related to accounts payable resulting from the higher level of operating expenses needed to support the higher sales level.

Net cash used by operating activities for the three months ended March 31, 2014 consisted of our net income of $0.9 million and non-cash expense items such as depreciation and amortization of our equipment and leasehold improvements of $2.7 million, provision for rental revenue adjustments of $1.7 million, provision for sales returns of $0.9 million, provision for doubtful accounts of $0.2 million , loss on disposal of rental units and other fixed assets of $0.3 million, and stock-based compensation of $0.1 million. The changes in operating assets consisted of ($8.2) million of which ($10.7) million was due to an increase in accounts receivable balances during this period. This was primarily due to a significant delay in billing for rental revenues associated with the implementation of our new medical billing system in the first quarter of 2014. We expect this trend to reverse in the second quarter of 2014.

Net cash provided by operating activities for the three months ended March 31, 2013 consisted of our net income of $0.7 million and non-cash expense items such as depreciation and amortization of our equipment and leasehold improvements of $1.7 million, provision for rental revenue adjustments of $1.2 million, provision for doubtful accounts of $0.5 million and provision for sales returns of $0.4 million. These items were partially offset by net changes in our operating assets and liabilities of ($1.8) million.

Net cash used in investing activities for each of the periods presented was primarily for the purchase of rental assets, research and development, manufacturing tooling, and computer equipment and software to support our expanding business.

For the three months ended March 31, 2014, we invested $2.9 million in rental assets and $0.2 million in other property and equipment and $0.2 million in intangible assets.

For the three months ended March 31, 2013, we invested $3.2 million in rental assets and $0.4 million in other property and equipment.

We expect to continue investing in property and equipment as we expand our operations. Other than the deployment of product for rental to our customers and the necessary manufacturing equipment and tooling for the launch of our next oxygen concentrator in development, our operations are inherently capital intensive due to our portions of revenue derived from our rental business model; investments will continue to be required in order to grow rental revenue.

Historically, we have funded our operations through our sales and rental revenue the issuance of preferred stock and the incurrence of indebtedness.

For the three months ended March 31, 2014, net cash provided by financing activities consisted primarily of $51.6 million of net proceeds from the initial public offering which closed on February 20, 2014 after commissions and expenses and $0.5 million from the proceeds from redeemable convertible preferred stock and common stock warrants that were exercised. This was partially offset by repayments of borrowings under our revolving credit and term loan agreement of ($1.4) million as existing balances and payback terms were not changed.

For the three months ended March 31, 2013, net cash used in financing activities consisted of the issuance of $0.9 million from proceeds received from convertible preferred stock warrants that were exercised and was partially offset by repayment of ($0.9) million of borrowings under our revolving credit and term loan agreement and repayment of ($0.1) million on the contractual obligation.

EBITDA and Adjusted EBITDA are financial measures that are not calculated in accordance with generally accepted accounting principles in the United States, or GAAP. We define EBITDA as net income or loss excluding interest income, interest expense, taxes and depreciation and amortization. Adjusted EBITDA also excludes the change in the fair value of our preferred stock warrant liability and stock-based compensation. Below, we have provided a reconciliation of EBITDA and Adjusted EBITDA the most directly comparable financial measure calculated and presented in accordance with GAAP. EBITDA and Adjusted EBITDA should not be considered alternatives to net income or loss or any other measure of financial performance calculated and presented in accordance with GAAP. Our EBITDA and Adjusted EBITDA may not be comparable to similarly titled measures of other organizations because other organizations may not calculate EBITDA and Adjusted EBITDA in the same manner as we calculate these measures.

We include EBITDA and Adjusted EBITDA in this Quarterly Report on Form 10-Q because they are important measures upon which our management assesses our operating performance. We use EBITDA and Adjusted EBITDA as key performance measures because we believe they facilitate operating performance comparisons from period to period by excluding potential differences primarily caused by variations in capital structures, tax positions, the impact of depreciation and amortization expense on our fixed assets, changes related to the fair value re-measurements of our preferred stock warrant, and the impact of stock-based compensation expense. Because EBITDA and Adjusted EBITDA facilitate internal comparisons of our historical operating performance on a more consistent basis, we also use EBITDA and Adjusted EBITDA for business planning purposes, to incentivize and compensate our management personnel, and in evaluating acquisition opportunities. In addition, we believe EBITDA and Adjusted EBITDA and similar measures are widely used by investors, securities analysts, ratings agencies, and other parties in evaluating companies in our industry as a measure of financial performance and debt-service capabilities.

Our use of EBITDA and Adjusted EBITDA have limitations as analytical tools, and you should not consider them in isolation or as a substitute for analysis of our results as reported under GAAP. Some of these limitations are:

In evaluating EBITDA and Adjusted EBITDA you should be aware that in the future we will incur expenses similar to the adjustments in this presentation. Our presentation of EBITDA and Adjusted EBITDA should not be construed as an inference that our future results will be unaffected by these expenses or any unusual or non-recurring items. When evaluating our performance, you should consider EBITDA and Adjusted EBITDA alongside other financial performance measures, including our net loss and other GAAP results.

The following table presents a reconciliation of EBITDA and Adjusted EBITDA to our net income, the most comparable GAAP measure, for each of the periods indicated:

	Three months ended March 31,
EBITDA	2014			2013
Net income	$	888		$	730
Non-GAAP adjustments:
Interest expense		133			104
Interest income		(6	)		(3	)
Provision for income taxes		577			31
Depreciation and amortization		2,658			1,661
EBITDA		4,250			2,523
Change in fair value of preferred stock warrant liability		(36	)		(20	)
Stock-based compensation		131			24
Adjusted EBITDA	$	4,345		$	2,527


	Three months ended March 31,
Pro-forma non-GAAP results of EPS calculation (1) (2)	2014			2013
Net loss attributable to common stockholders - GAAP	$	(99	)	$	(993	)
Add deemed dividend on redeemable convertible preferred stock		987			1,723
Pro-forma net income attributable to common stockholders	$	888		$	730

Pro-forma net income per share - basic common stock	$	0.05		$	0.05
Pro-forma net income per share - diluted common stock	$	0.05		$	0.05

Denominator:
Pro-forma weighted-average common shares - basic common stock		16,404,677			14,509,408
Pro-forma weighted-average common shares - diluted common stock		18,373,886			15,146,745

We are exposed to various market risks, including fluctuation in interest rates and foreign currency exchange rates. Market risk is the potential loss arising from adverse changes in market rates and prices. Prices for our products are denominated in U.S. dollars and, as a result, we do not face significant risk with respect to foreign currency exchange rates.

The principal market risk we face is interest rate risk. We had cash and cash equivalents of $59.6 million as of March 31, 2014, which consisted of highly-liquid investments with an original maturity of three months or less. The primary goals of our investment policy are liquidity and capital preservation. We do not enter into investments for trading or speculative purposes. We believe that we do not have any material exposure to changes in the fair value of these assets as a result of changes in interest rates due to the short-term nature of our cash and cash equivalents. Declines in interest rates, however, would reduce future investment income. If overall interest rates had decreased by 10% during the periods presented, our interest income would not have been materially affected.

As of March 31, 2014, the total principal and accrued interest outstanding under our term loan borrowings was $8.4 million. The interest rates on our term borrowings under our revolving credit and term loan agreement bear interest at the base rate, which is a rate equal to the applicable margin plus the greater of (i) the prime rate, (ii) the federal funds effective rate, as defined in the agreements, plus 1% and (iii) the daily adjusting LIBOR rate, plus 1%. The applicable margins for Terms Loans A, B, and C are 1.25%, 2.5% and 2.25%, respectively. If overall interest rates had increased by 10% during the periods presented, our interest expense would not have been materially affected.

To date, our international customer and distributor agreements have been denominated almost exclusively in U.S. dollars. Accordingly, we have limited exposure to foreign currency exchange rates. The effect of a 10% adverse change in exchange rates on foreign denominated cash, receivables and payables as of March 31, 2014 and December 31, 2013 would not have been material. As our operations in countries outside of the United States grow, our results of operations and cash flows will be subject to fluctuations due to changes in foreign currency exchange rates, which could harm our business in the future. To date, we have not entered into any material foreign currency hedging contracts although we may do so in the future.

In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives. In addition, the design of disclosure controls and procedures must reflect the fact that there are resource constraints and that management is required to apply its judgment in evaluating the benefits of possible controls and procedures relative to their costs.

The Company maintains a system of disclosure controls and procedures (as defined in Rule 13a-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act) which are designed to provide reasonable assurance that information required to be disclosed in the reports that the Company files or submits under the Exchange Act, is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. These disclosure controls and procedures include, among other processes, controls and procedures designed to ensure that information required to be disclosed in the reports that the Company files or submits under the Exchange Act is accumulated and communicated to management, including the principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

The Company carried out an evaluation, under the supervision and with the participation of management, including the principal executive officer and the principal financial officer, of the effectiveness of the design and operation of our disclosure controls and procedures as of March 31, 2014 pursuant to Exchange Act Rule 13a-15. Based upon that evaluation, the principal executive officer and the principal financial officer concluded that the Company’s disclosure controls and procedures were effective at the reasonable assurance level as of the end of the period covered by this report to ensure that the information required to be disclosed by us in reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and to ensure that the information required to be disclosed by us in reports that we file or submit under the Exchange Act is accumulated and communicated to our management, including the principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

There has been no change in our internal control over financial reporting during the quarter ended March 31, 2014 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

On November 4, 2011, we filed a lawsuit in the United States District Court for the Central District of California against Inova Labs Inc., or Defendant, for infringement of two of our patents. The case, Inogen Inc. v. Inova Labs Inc., Case No. 8:11-cv-01692-JST-AN, or the Lawsuit, involves U.S. Patent Nos. 7,841,343, entitled “Systems and Methods For Delivering Therapeutic Gas to Patients”, or the ’343 patent, and 6,605,136 entitled “Pressure Swing Adsorption Process Operation And Optimization”, or the ’136 patent. We alleged in the Lawsuit that certain of Defendant’s oxygen concentrators infringe various claims of the ’343 and ’136 patents. The Lawsuit seeks damages, injunctive relief, costs and attorney fees.

The Defendant has answered the complaint, denying infringement and asserting various sets of defenses including non-infringement, invalidity and unenforceability, patent misuse, unclean hands, laches and estoppel. The Defendant also filed counterclaims against us alleging patent invalidity, non-infringement and inequitable conduct. We denied the allegations in the Defendant’s counterclaims. We have filed a motion to dismiss the Defendant’s inequitable conduct counterclaim.

The Defendant filed a request with the U.S. Patent and Trademark Office seeking an inter partes reexamination of the ’343 and ’136 patents. The Defendant also filed a motion to stay the Lawsuit pending outcome of the reexamination. On March 20, 2012, the court granted the Defendant’s motion to stay the Lawsuit pending outcome of the reexamination and also granted our motion to dismiss the Defendant’s inequitable conduct counterclaim.

The Company is party to various other legal proceedings arising in the normal course of business. The Company carries insurance, subject to deductibles under the specified policies, to protect against losses from certain types of legal claims. The Company does not anticipate that any of these proceedings will have a material impact on the Company.

We operate in a rapidly changing environment that involves numerous uncertainties and risks. The following risks and uncertainties may have a material and adverse effect on our business, financial condition or results of operations. You should consider these risks and uncertainties carefully, together with all of the other information included or incorporated by reference in this Form 10-Q. If any of the risks or uncertainties we face were to occur, the trading price of our securities could decline, and you may lose all or part of your investment.

A significant majority of our customers have health coverage under the Medicare program, and recently enacted and future changes in the reimbursement rates or payment methodologies under Medicare and other government programs have affected and could continue to materially and adversely affect our business and operating results.

As a provider of oxygen product rentals, we have historically depended heavily on Medicare reimbursement as a result of the higher proportion of elderly persons suffering from chronic respiratory conditions. Medicare Part B, or Supplementary Medical Insurance Benefits, provides coverage to eligible beneficiaries that include items of durable medical equipment for use in the home, such as oxygen equipment and other respiratory devices. We believe that more than 60% of oxygen therapy patients in the United States have primary coverage under Medicare Part B. For the three months ended March 31, 2014 and March 31, 2013, we derived approximately 21.5%, and 26.3%, respectively, of our total revenue from Medicare’s service reimbursement programs (net of patient co-insurance obligations). There are increasing pressures on Medicare to control healthcare costs and to reduce or limit reimbursement rates for home medical products.

Legislation, including the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, the Deficit Reduction Act of 2005, the Medicare Improvements for Patients and Providers Act of 2008, and the Patient Protection and Affordable Care Act, contain provisions that directly impact reimbursement for the durable medical equipment products provided by us:


(dollars in hundreds)	2009			2010			2011			2012			2013			2014
Stationary oxygen percentage rate changes 2009 - 2010		-2.30	%		-1.50	%
Stationary oxygen payment changes 2010 - 2011	$	175.79		$	173.17
Stationary oxygen percentage rate changes 2011 - 2012								0.10	%		1.60	%		0.70	%
Stationary oxygen payment changes 2011 - 2012							$	173.31		$	176.06		$	177.36
Stationary oxygen percentage rate changes 2013 - 2014																	0.50	%
Stationary oxygen payment changes 2013 - 2014																$	178.24

These legislative provisions, as currently in effect and when fully implemented, have had and will continue to have a material and adverse effect on our business, financial condition and operating results.

Due to budgetary shortfalls, many states are considering, or have enacted, cuts to their Medicaid programs. These cuts have included, or may include, elimination or reduction of coverage for our products, amounts eligible for payment under co-insurance arrangements, or payment rates for covered items. Continued state budgetary pressures could lead to further reductions in funding for the reimbursement for our products which, in turn, would adversely affect our business, financial conditions, and results of operations.

The implementation of the competitive bidding process under Medicare could negatively affect our business and financial condition.

The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 required the Secretary of Health and Human Services to establish and implement programs under which competitive acquisition areas are established throughout the United States for purposes of awarding contracts for the furnishing of competitively priced items of durable medical equipment, including oxygen equipment.

The Centers for Medicare & Medicaid Services, the agency responsible for administering the Medicare program, conducts a competition for each competitive acquisition area under which providers submit bids to supply certain covered items of durable medical equipment. Successful bidders must meet certain program quality standards in order to be awarded a contract and only successful bidders can supply the covered items to Medicare beneficiaries in the acquisition area. There are, however, regulations in place that allow non-contracted providers to continue to provide products and services to their existing customers at the new competitive bidding payment amounts. The contracts are expected to be re-bid every three years. The Centers for Medicare & Medicaid Services is required to award contracts to multiple entities submitting bids in each area for an item or service, but has the authority to limit the number of contractors in a competitive acquisition area to the number it determines to be necessary to meet projected demand.

Although the Centers for Medicare & Medicaid Services concluded the bidding process for the first round of Metropolitan Statistical Areas in September 2007, in July 2008, Congress enacted Medicare Improvements for Patients and Providers Act of 2008, which retroactively delayed the implementation of competitive bidding. Medicare Improvements for Patients and Providers Act of 2008 also reduced Medicare prices nationwide by 9.5% beginning in 2009 for the product categories, including oxygen, that were initially included in competitive bidding.

In 2009, the Centers for Medicare & Medicaid Services implemented a new bidding process in nine Metropolitan Statistical Areas, covering approximately 9% of the Medicare oxygen market. Reimbursement rates from the re-bidding process were publicly released by the Centers for Medicare & Medicaid Services on June 30, 2010. The Centers for Medicare & Medicaid Services announced average savings of approximately 35% off the current standard Medicare payment rates in effect for the product categories included in competitive bidding. As of January 1, 2011, these payment rates were in effect in the nine markets only. We were offered six three-year contracts to provide oxygen equipment in six of the nine markets, and we accepted and signed those contracts.

The Centers for Medicare & Medicaid Services implemented the second phase of competitive bidding in an additional 100 competitive bidding areas covering approximately 50% of the Medicare oxygen market, with three-year contracts effective July 1, 2013. The Centers for Medicare & Medicaid Services announced average savings of approximately 45% off the current standard Medicare payment rates in effect for the product categories included in competitive bidding. As of July 1, 2013, these payment rates were in effect in the 100 competitive bidding areas. We were offered 89 contracts to provide oxygen equipment in 89 of the 100 Competitive Bidding Areas, and we accepted and signed those contracts.

Round one re-competes rates went into effect January 1, 2014; reimbursement rates from the re-bidding process were publicly released by the Centers for Medicare & Medicaid Services on October 1, 2013. The Centers for Medicare & Medicaid Services announced average savings of approximately 37% off the current standard Medicare payment rates in effect from the product categories included in competitive bidding. We were offered 3 contracts to provide respiratory equipment in 3 of the 9 competitive bidding areas, and we accepted and signed those contracts. We are required to be able to supply additional respiratory products such as sleep and aerosol therapy, which have lower margins than our existing products. This could have a negative impact on our financial conditions and results of operations.

The Patient Protection and Affordable Care Act legislation requires the Centers for Medicare & Medicaid Services to expand competitive bidding further to additional geographic markets or to use competitive bid pricing information to adjust the payment amounts otherwise in effect for areas that are not competitive acquisition areas by January 1, 2016.

Although we continue to monitor developments regarding the implementation of the competitive bidding program, we cannot predict the outcome of the competitive bidding program on our business when fully implemented, nor the Medicare payment rates that will be in effect in future years for the items subjected to competitive bidding, including our products. We expect that the stationary oxygen and non-delivery ambulatory oxygen payment rates will continue to fluctuate and a large negative payment adjustment could adversely affect our business, financial conditions and results of operations.

We face intense national, regional and local competition and if we are unable to compete successfully, it could have an adverse effect on our revenue, revenue growth rate, if any, and market share.

The oxygen therapy market is a highly competitive industry. We compete with a number of manufacturers and distributors of portable oxygen concentrators, as well as providers of other oxygen therapy solutions such as home delivery of oxygen tanks or cylinders.

Our significant manufacturing competitors are Invacare Corporation, Respironics (a subsidiary of Koninklijke Philips N.V.), AirSep Corporation and SeQual Technologies (subsidiaries of Chart Industries, Inc.), Inova Labs Inc., and DeVilbiss Healthcare. Given the relatively straightforward regulatory path in the oxygen therapy device manufacturing market, we expect that the industry will become increasingly competitive in the future. Manufacturing companies compete for sales to providers primarily on the basis of product features, service and price.

Lincare Inc., Apria Healthcare, Inc. Rotech Healthcare, Inc. and American HomePatient, Inc. are among the market leaders in providing oxygen therapy for many years, while the remaining oxygen therapy market is serviced by local providers. Because many oxygen therapy providers were either excluded from contracts in the Medicare competitive bidding process, or will have difficulty providing service at the prevailing Medicare reimbursement rates, we expect more industry consolidation. Oxygen therapy providers compete primarily on the basis of product features and service, rather than price, since reimbursement levels are established by Medicare and Medicaid, or by the individual determinations of private payors.

Some of our competitors are large, well-capitalized companies with greater resources than we have. As a consequence, they are able to spend more aggressively on product development, marketing, sales and other product initiatives than we can. Some of these competitors have:

As a result, our competitors may be able to respond more quickly and effectively than we can to new or changing opportunities, technologies, standard regulatory and reimbursement development and customer requirements. In light of these advantages that our competitors maintain, even if our technology and direct-to-consumer distribution strategy is more effective than the technology and distribution strategy of our competitors, current or potential customers might accept competitor products and services in lieu of purchasing our products. We anticipate that we will face increased competition in the future as existing companies and competitors develop new or improved products and distribution strategies and as new companies enter the market with new technologies and distribution strategies. We may not be able to compete effectively against these organizations. Our ability to compete successfully and to increase our market share is dependent upon our reputation for providing responsive, professional and high-quality products and services and achieving strong customer satisfaction. Increased competition in the future could adversely affect our revenue, revenue growth rate, margins and market share.

Healthcare reform measures may have a material adverse effect on our business and results of operations.

In the United States, the legislative landscape, particularly as it relates to healthcare regulation and reimbursement coverage, continues to evolve. In March 2010, the Patient Protection and Affordable Care Act was passed, which has the potential to substantially change healthcare financing by both governmental and private insurers, and significantly impact the U.S. medical device industry. As discussed above, the Patient Protection and Affordable Care Act, among other things, imposes a new excise tax, which began in 2013, on entities that manufacture, produce or import medical devices in an amount equal to 2.3% of the price for which such devices are sold in the United States, however oxygen products such as ours were exempt. In addition, as discussed above, the Patient Protection and Affordable Care Act also expands the round two of competitive bidding to a total of 91 competitive bidding areas, and by 2016, the process must be nationalized or prices in non-competitive bidding areas must be adjusted to match competitive bidding prices.

In addition, other legislative changes have been proposed and adopted in the United States since the Patient Protection and Affordable Care Act was enacted. On August 2, 2011, the Budget Control Act of 2011 among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers up to 2% per fiscal year, which went into effect on April 1, 2013. On January 2, 2013, President Obama signed into law the American Taxpayer Relief Act of 2012 which, among other things, further reduced Medicare payments to certain providers, including physicians, hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our products or additional pricing pressures.

If we are unable to continue to enhance our existing products and develop and market new products that respond to customer needs and preferences and achieve market acceptance, we may experience a decrease in demand for our products and our business could suffer.

We may not be able to compete as effectively with our competitors, and ultimately satisfy the needs and preferences of our customers, unless we can continue to enhance existing products and develop new innovative products. Product development requires significant financial, technological, and other resources. While we expended $0.6 million and $0.5 million for research and development efforts for the three months ended March 31, 2014 and March 31, 2013, respectively, we cannot assure you that this level of investment in research and development will be sufficient to maintain a competitive advantage in product innovation, which could cause our business to suffer. Product improvements and new product introductions also require significant planning, design, development, and testing at the technological, product, and manufacturing process levels and we may not be able to timely develop product improvements or new products. Our competitors’ new products may beat our products to market, be more effective with more features, obtain better market acceptance, or render our products obsolete. Any new products that we develop may not receive market acceptance or otherwise generate any meaningful sales or profits for us relative to our expectations based on, among other things, existing and anticipated investments in manufacturing capacity and commitments to fund advertising, marketing, promotional programs, and research and development.

We depend upon reimbursement from Medicare, private payors and Medicaid for a significant portion of our revenue, and if we fail to manage the complex and lengthy reimbursement process, our business and operating results could suffer.

A significant portion of our revenue is derived from reimbursement by third-party payors. We accept assignment of insurance benefits from customers and, in a majority of cases, invoice and collect payments directly from Medicare, private payors and Medicaid, as well as from customers under co-insurance provisions. For the three months ended March 31, 2014 and March 31, 2013, approximately 37.1% and 43.5% of our total revenue was derived from Medicare, private payors, Medicaid, and individual customers who receive reimbursement payments.

Our financial condition and results of operations may be affected by the healthcare industry’s reimbursement process, which is complex and can involve lengthy delays between the time that a product is delivered to the consumer and the time that the reimbursement amounts are settled. Depending on the payor, we may be required to obtain certain payor-specific documentation from physicians and other healthcare providers before submitting claims for reimbursement. Certain payors have filing deadlines and they will not pay claims submitted after such time. We are also subject to extensive pre-payment and post-payment audits by governmental and private payors that could result in material delays, refunds of monies received or denials of claims submitted for payment under such third-party payor programs and contracts. We cannot ensure that we will be able to continue to effectively manage the reimbursement process and collect payments for our products promptly. If we fail to manage the complex and lengthy reimbursement process, it would adversely affect our business, financial conditions, and results of operations.

Failure to obtain private payor contracts and future reductions in reimbursement rates from private payors could have a material adverse effect on our financial condition and operating results.

A portion of our revenue is derived from private payors. Based on our patient population, we estimate at least 30% of potential customers have non-Medicare insurance coverage, and we believe these patients represent a younger and more active patient population that will be drawn to the quality-of-life benefits of our solution. Failing to maintain and obtain private payor contracts from private insurance companies and employers and secure in-network provider status could have a material adverse effect on our financial condition and operating results. In addition, private payors are under pressure to increase profitability and reduce costs. In response, certain private payors are limiting coverage or reducing reimbursement rates for the products we provide. We believe that private payor reimbursement levels will generally be reset in accordance with the Medicare payment amounts determined by competitive bidding. We cannot predict the extent to which reimbursement for our products will be affected by competitive bidding or by initiatives to reduce costs for private payors. Failure to obtain or maintain private payor contracts or the unavailability of third-party coverage or inadequacy of reimbursement for our products would adversely affect our business, financial conditions, and results of operations.

We obtain some of the components, subassemblies and completed products included in our Inogen One systems from a single source or a limited group of manufacturers or suppliers, and the partial or complete loss of one of these manufacturers or suppliers could cause significant production delays, an inability to meet customer demand and a substantial loss in revenue.

We utilize single source suppliers for some of the components and subassemblies we use in our Inogen One systems. We have qualified alternate sources of supply sufficient to support future needs and we have taken other mitigating steps to reduce the impact of a change in supplier; however, there may be delays in switching to these alternative suppliers if our primary source is terminated without notice. Our dependence on single source suppliers of components may expose us to several risks, including, among other things:

In addition, we may be deemed to manufacture or contract to manufacture products that contain certain minerals that have been designated as “conflict minerals” under the Dodd-Frank Wall Street Reform and Consumer Protection Act. As a result, in future periods, we may be required to diligence the origin of such minerals and disclose and report whether or not such minerals originated in the Democratic Republic of the Congo or adjoining countries. The implementation of these new requirements could adversely affect the sourcing, availability, and pricing of minerals used in the manufacture of our products. In addition, we may incur additional costs to comply with the disclosure requirements, including costs related to determining the source of any of the relevant minerals and metals used in our products.

If any of these risks materialize, costs could significantly increase and our ability to meet demand for our products could be impacted. If we are unable to satisfy commercial demand for our Inogen One systems in a timely manner, our ability to generate revenue would be impaired, market acceptance of our products could be adversely affected, and customers may instead purchase or use alternative products. In addition, we could be forced to secure new or alternative components and subassemblies through a replacement supplier. Finding alternative sources for these components and subassemblies could be difficult in certain cases and may entail a significant amount of time and disruption. In some cases, we would need to change the components or subassemblies if we sourced them from an alternative supplier. This, in turn, could require a redesign of our Inogen One systems and, potentially, require additional FDA clearance or approval before we could use any redesigned product with new components or subassemblies, thereby causing further costs and delays that could adversely affect our business, financial condition and operating results.

We do not have long-term supply contracts with many of our third-party suppliers.

We purchase components and subassemblies from third-party suppliers, including some of our single source suppliers, through purchase orders and do not have long-term supply contracts with many of these third-party suppliers. Many of our third-party suppliers, therefore, are not obligated to perform services or supply products to us for any specific period, in any specific quantity or at any specific price, except as may be provided in a particular purchase order. We do not maintain large volumes of inventory from most of these suppliers. If we inaccurately forecast demand for components or subassemblies, our ability to manufacture and commercialize our Inogen One systems could be delayed and our competitive position and reputation could be harmed. In addition, if we fail to effectively manage our relationships with these suppliers, we may be required to change suppliers which would be time consuming and disruptive and could adversely affect our business, financial condition and operating results.

If we fail to comply with U.S. export control and economic sanctions or fail to expand and maintain an effective sales force or successfully develop our international distribution network, our business, financial condition and operating results may be adversely affected.

We currently derive the majority of our revenue from rentals or sales generated from our own direct sales force. Failure to maintain or expand our direct sales force could adversely impact our financial and operating performance. Additionally, we use international distributors to augment our sales efforts, certain of which are exclusive distributors in certain foreign countries. We cannot assure you that we will be able to successfully develop our relationships with third-party distributors internationally. In addition, we are subject to United States export control and economic sanctions laws relating to the sale of our products, the violation of which could result in substantial penalties being imposed against us. In particular, we have secured annual export licenses from the U.S. Treasury Department’s Office of Foreign Assets Control to sell our products to a distributor and hospital and clinic end-users in Iran. The use of this license requires us to observe strict conditions with respect to products sold, end-user limitations and payment requirements. Although we believe we have maintained compliance with license requirements, there can be no assurance that the license will not be revoked, be renewed in the future or that we will remain in compliance. More broadly, if we fail to comply with export control laws or successfully develop our relationship with international distributors, our sales could fail to grow or could decline, and our ability to grow our business could be adversely affected. Distributors that are in the business of selling other medical products may not devote a sufficient level of resources and support required to generate awareness of our products and grow or maintain product sales. If our distributors are unwilling or unable to market and sell our products, or if they do not perform to our expectations, we could experience delayed or reduced market acceptance and sales of our products.

We may be subject to substantial warranty or product liability claims or other litigation in the ordinary course of business that may adversely affect our business, financial condition and operating results.

As manufacturers of medical devices, we may be subject to substantial warranty or product liability claims or other litigation in the ordinary course of business that may require us to make significant expenditures to defend these claims or pay damage awards. For example, our Inogen One systems contain lithium ion batteries, which, under certain circumstances, can be a fire hazard. We, as well as our key suppliers, maintain product liability insurance, but this insurance is limited in amount and subject to significant deductibles. There is no guarantee that insurance will be available or adequate to protect against all claims. Our insurance policies are subject to annual renewal and we may not be able to obtain liability insurance in the future on acceptable terms or at all. In addition, our insurance premiums could be subject to increases in the future, which may be material. If the coverage limits are inadequate to cover our liabilities or our insurance costs continue to increase as a result of warranty or product liability claims or other litigation, then our business, financial condition and operating results may be adversely affected.

Increases in our operating costs could have a material adverse effect on our business, financial condition and operating results.

Reimbursement rates are established by fee schedules mandated by Medicare, private payors and Medicaid are likely to remain constant or decrease due, in part, to federal and state government budgetary constraints. As a result, with respect to Medicare and Medicaid related revenue, we are not able to offset the effects of general inflation on our operating costs through increases in prices for our products. In particular, labor and related costs account for a significant portion of our operating costs and we compete with other health providers to attract and retain qualified or skilled personnel and with various industries for administrative and service employees. This competitive environment could result in increased labor costs. As such, we must control our operating costs, particularly labor and related costs, and failing to do so could adversely affect our financial conditions and results of operations.

We depend on the services of our senior executives and other key technical personnel, the loss of whom could negatively affect our business.

Our success depends upon the skills, experience and efforts of our senior executives and other key technical personnel, including certain members of our engineering staff, and our sales and marketing executives. Much of our corporate expertise is concentrated in relatively few employees, the loss of which for any reason could negatively affect our business. Competition for our highly skilled employees is intense and we cannot prevent the resignation of any employee. We do not maintain “key man” life insurance on any of our senior executives. None of our senior executive team is bound by written employment contracts to remain with us for a specified period. In addition, we have not entered into non-compete agreements with members of our senior management team. The loss of any member of our senior management team could harm our ability to implement our business strategy and respond to the market conditions in which we operate.

We have incurred losses since inception until fiscal year 2012, and we have only recently achieved profitability.

We have a limited operating history and had incurred significant net losses in each fiscal year until fiscal year 2012, when we achieved positive net income. As of March 31, 2014, we had an accumulated deficit of $62.6 million. These net losses have resulted principally from costs incurred in our research and development programs and from our selling, general and administrative expenses. We expect to incur increases in expenses for research and development and significant expansion of our sales and marketing capabilities. Additionally, since completing our initial public offering, we expect that our selling, general and administrative expenses will increase due to the additional operational and reporting costs associated with being a public company. Because of the numerous risks and uncertainties associated with our commercialization efforts and future product development, we are unable to predict if we will maintain or increase our net income.

Our financial results may vary significantly from quarter-to-quarter due to a number of factors, which may lead to volatility in our stock price.

Our quarterly revenue and results of operations have varied in the past and may continue to vary significantly from quarter-to-quarter. This variability may lead to volatility in our stock price as research analysts and investors respond to these quarterly fluctuations. These fluctuations are due to numerous factors, including: fluctuations in consumer demand for our products; seasonal cycles in consumer spending; our ability to design, manufacture and deliver products to our consumers in a timely and cost-effective manner; quality control problems in our manufacturing operations; our ability to timely obtain adequate quantities of the components used in our products; new product introductions and enhancements by us and our competitors; unanticipated increases in costs or expenses; and fluctuations in foreign currency exchange rates. For example, we typically experience higher sales in the second quarter, as a result of consumers traveling and vacationing during the summer months. The foregoing factors are difficult to forecast, and these, as well as other factors, could materially and adversely affect our quarterly and annual results of operations. In addition, a significant amount of our operating expenses are relatively fixed due to our manufacturing, research and development, and sales and general administrative efforts. Any failure to adjust spending quickly enough to compensate for a revenue shortfall could magnify the adverse impact of such revenue shortfall on our results of operations. Our results of operations may not meet the expectations of research analysts or investors, in which case the price of our common stock could decrease significantly.

The terms of our revolving credit and term loan agreement may restrict our current and future operations, and could affect our ability to respond to changes in our business and to manage our operations.

We are parties to an amended and restated revolving credit and term loan agreement with Comerica Bank as administrative agent, which we refer to as our revolving credit and term loan agreement. The agreement provides for a previously existing term loan in the amount of $3.0 million, another previously existing term loan in the amount of $8.0 million and a new term loan facility in the amount of $12.0 million. As of March 31, 2014, we had term loan borrowings outstanding under the agreement of $8.4 million, which included $0.2 million and $3.1 million under the pre-existing term loans and $5.2 million under the new term loan. The agreement also provides for a $1.0 million revolving line of credit, none of which was outstanding as of March 31, 2014. The revolver expired on October 13, 2013 and we have no plans to renew or replace it. The agreement is secured by all or substantially all of our assets.

Pursuant to the agreement, we are subject to certain financial covenants relating to liquidity, debt service, and leverage ratios. The liquidity ratio is the ratio of (i) liquidity (cash plus eligible accounts receivable) to (ii) the current portion of all indebtedness owed to the lenders. The debt service coverage ratio is the ratio on a basis of (a) Adjusted EBITDA, less (i) cash capital expenditures (including rental equipment) and (ii) taxes paid or payable, to (b) the sum of cash principal payments plus interest expense paid or payable, all such items in clauses (a) and (b) measured on an annualized trailing six (6) months basis; provided that cash capital expenditures shall not be subtracted from clause (a) hereof so long as we maintain at least $1.5 million in unrestricted cash during the entire relevant fiscal period. The senior leverage ratio is the ratio of (a) funded debt basis to (b) Adjusted EBITDA measured on an annualized trailing six (6) months basis.

The agreement contains events of default customary for transactions of this type, including nonpayment, misrepresentation, breach of covenants, material adverse effect and bankruptcy. As of March 31, 2014, we had an outstanding balance of $8.4 million under the term loans. In the event we fail to satisfy our covenants, or otherwise go into default, Comerica Bank has a number of remedies, including sale of our assets and acceleration of all outstanding indebtedness. Certain of these remedies would likely have a material adverse effect on our business. As of March 31, 2014, in order to be in compliance with the liquidity requirements, debt service ratios, and leverage ratios of existing debt obligations, we were required to maintain $3.6 million in unaudited Adjusted EBITDA in the previous six months, and we had $7.5 million in actual unaudited Adjusted EBITDA, and we were required to maintain $7.2 million of cash and qualified accounts receivable, and we had $68.6 million of actual cash and qualified accounts receivable.

An adverse outcome of a sales and use tax audit could have a material adverse effect on our results of operations and financial condition.

The California State Board of Equalization conducted a sales and use tax audit of our operations in California in 2008. As a result of the audit, the California State Board of Equalization confirmed that our sales are not subject to California sales and use tax. We believe that our sales in other states should not be subject to sales and use tax. There can be no assurance, however, that other states may agree with our position and we may be subject to an audit that may not be resolved in our favor. Such an audit could be expensive and time-consuming and result in substantial management distraction. If the matter were to be resolved in a manner adverse to us, it could have a material adverse effect on our results of operations and financial position.

Our ability to use net operating losses to offset future taxable income may be subject to certain limitations.

As of December 31, 2013, we had federal and state net operating loss carryforwards, or NOLs, of approximately $56.7 million and $54.9 million, respectively. Theyexpire in various years beginning in 2022 and 2013, respectively if not utilized. In general, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, a corporation that undergoes an “ownership change” is subject to limitations on its ability to utilize its pre-change NOLs to offset future taxable income. In general, an “ownership change” occurs if there is a cumulative change in our ownership by “5% shareholders” that exceeds 50 percentage points over a rolling three-year period. Our existing NOLs may be subject to limitations arising from previous ownership changes, and if we undergo one or more ownership changes our ability to utilize NOLs could be further limited by Section 382 of the Code. Even after factoring in these limitations, the Company was able to determine based on future projections of income that it is more likely than not that all of its federal NOLs will be utilized before they expire and therefore determined that releasing the valuation allowance relating to these NOLs was appropriate during this period. However, the Company determined that some of its California NOLs will expire unused and therefore has maintained a valuation allowance of $4.1 million relating to these NOLs.

We are subject to extensive federal and state regulation, and if we fail to comply with applicable regulations, we could suffer severe criminal or civil sanctions or be required to make significant changes to our operations that could adversely affect our business, financial condition and operating results.

The federal government and all states in which we currently operate regulate various aspects of our business. In particular, our sales and customer service centers are subject to federal laws that regulate interstate motor-carrier transportation. Our operations also are subject to state laws governing, among other things, distribution of medical equipment and certain types of home health activities, and we are required to obtain and maintain licenses in each state to act as a durable medical equipment supplier. Certain of our employees are subject to state laws and regulations governing the professional practices of respiratory therapy.

As a healthcare provider participating in governmental healthcare programs, we are subject to laws directed at preventing fraud and abuse, which subject our marketing, billing, documentation and other practices to government scrutiny. To ensure compliance with Medicare, Medicaid and other regulations, government agencies or their contractors often conduct routine audits and request customer records and other documents to support our claims submitted for payment of services rendered. Government agencies or their contractors also periodically open investigations and obtain information from healthcare providers. Violations of federal and state regulations can result in severe criminal, civil and administrative penalties and sanctions, including debarment, suspension or exclusion from Medicare, Medicaid and other government reimbursement programs, any of which would have a material adverse effect on our business.

Changes in healthcare laws and regulations and new interpretations of existing laws and regulations may affect permissible activities, the relative costs associated with doing business, and reimbursement amounts paid by federal, state and other third-party payors. There have been and will continue to be regulatory initiatives affecting our business and we cannot predict the extent to which future legislation and regulatory changes could have a material adverse effect on our business.

We are subject to burdensome and complex billing and record-keeping requirements in order to substantiate our claims for payment under federal, state and commercial healthcare reimbursement programs, and our failure to comply with existing requirements, or changes in those requirements or interpretations thereof, could adversely affect our business, financial condition and operating results.

We are subject to burdensome and complex billing and record-keeping requirements in order to substantiate our claims for payment under federal, state and commercial healthcare reimbursement programs. Our records also are subject to routine and other reviews by third-party payors, which can result in delays in payments or refunds of paid claims. For example, we have also experienced a significant increase in pre-payment reviews of our claims by the Durable Medical Equipment Medicare Administrative Contractors, which has caused substantial delays in the collection of our Medicare accounts receivable as well as related amounts due under supplemental insurance plans.

Current law provides for a significant expansion of the government’s auditing and oversight of suppliers who care for patients covered by various government healthcare programs. Examples of this expansion include audit programs being implemented by the Durable Medical Equipment Medicare Administrative Contractors, the Zone Program Integrity Contractors, the Recovery Audit Contractors, and the Comprehensive Error Rate Testing contractors, operating under the direction of the Centers for Medicare & Medicaid Services.

We have been informed by these auditors that healthcare providers and suppliers of certain durable medical equipment product categories are expected to experience further increased scrutiny from these audit programs. When a government auditor ascribes a high billing error rate to one or more of our locations, it generally results in protracted pre-payment claims review, payment delays, refunds and other payments to the government and/or our need to request more documentation from providers than has historically been required. It may also result in additional audit activity in other company locations in that state or Durable Medical Equipment Medicare Administrative Contractors jurisdiction. We cannot currently predict the adverse impact that these audits, methodologies and interpretations might have on our business, financial condition or operating results, but such impact could be material.

We are subject to significant regulation by numerous government agencies, including the U.S. Food and Drug Administration, or FDA. We cannot market or commercially distribute our products without obtaining and maintaining necessary regulatory clearances or approvals.

Our Inogen One systems are medical devices subject to extensive regulation in the United States and in the foreign markets where we distribute our products. The FDA and other U.S. and foreign governmental agencies regulate, among other things, with respect to medical devices:

Before we can market or sell a medical device in the United States, we must obtain either clearance from the FDA under Section 510(k) of the Federal Food, Drug, and Cosmetic Act, or the FDCA, or approval of a pre-market approval, application from the FDA, unless an exemption from pre-market review applies. In the 510(k) clearance process, the FDA must determine that a proposed device is “substantially equivalent” to a device legally on the market, known as a “predicate” device, with respect to intended use, technology and safety and effectiveness, in order to clear the proposed device for marketing. Clinical data is sometimes required to support substantial equivalence. The pre-market approval pathway requires an applicant to demonstrate the safety and effectiveness of the device based, in part, on extensive data, including, but not limited to, technical, preclinical, clinical trial, manufacturing and labeling data. The pre-market approval process is typically required for devices that are deemed to pose the greatest risk, such as life-sustaining, life-supporting or implantable devices. Products that are approved through a pre-market approval application generally need FDA approval before they can be modified. Similarly, some modifications made to products cleared through a 510(k) may require a new 510(k). Both the 510(k) and pre-market approval processes can be expensive and lengthy and require the payment of significant fees, unless an exemption applies. The FDA’s 510(k) clearance process usually takes from three to 12 months, but may take longer. The process of obtaining a pre-market approval is much more costly and uncertain than the 510(k) clearance process and generally takes from one to three years, or longer, from the time the application is submitted to the FDA until an approval is obtained. The process of obtaining regulatory clearances or approvals to market a medical device can be costly and time consuming, and we may not be able to obtain these clearances or approvals on a timely basis, if at all.

In the United States, our currently commercialized products are marketed pursuant to pre-market clearance under Section 510(k) of the FDCA. If the FDA requires us to go through a lengthier, more rigorous examination for future products or modifications to existing products than we had expected, our product introductions or modifications could be delayed or canceled, which could cause our sales to decline. In addition, the FDA may determine that future products will require the more costly, lengthy and uncertain pre-market approval process. Although we do not currently market any devices under a pre-market approval, the FDA may demand that we obtain a pre-market approval prior to marketing certain of our future products. In addition, if the FDA disagrees with our determination that a product we currently market is subject to an exemption from pre-market review, the FDA may require us to submit a 510(k) or pre-market approval application in order to continue marketing the product. Further, even with respect to those future products where a pre-market approval is not required, we cannot assure you that we will be able to obtain the 510(k) clearances with respect to those products.

The FDA can delay, limit or deny clearance or approval of a device for many reasons, including:

In addition, the FDA may change its clearance and approval policies, adopt additional regulations or revise existing regulations, or take other actions which may prevent or delay approval or clearance of our products under development or impact our ability to modify our currently approved or cleared products on a timely basis. For example, in response to industry and healthcare provider concerns regarding the predictability, consistency and rigor of the 510(k) regulatory pathway, the FDA initiated an evaluation of the program, and in January 2011, announced several proposed actions intended to reform the review process governing the clearance of medical devices. The FDA intends these reform actions to improve the efficiency and transparency of the clearance process, as well as bolster patient safety. Some of these proposals, if enacted, could impose additional regulatory requirements upon us which could delay our ability to obtain new 510(k) clearances, increase the costs of compliance or restrict our ability to maintain our current clearances. In addition, as part of the Food and Drug Administration Safety and Innovation Act, Congress reauthorized the Medical Device User Fee Amendments with various FDA performance goal commitments and enacted several “Medical Device Regulatory Improvements” and miscellaneous reforms which are further intended to clarify and improve medical device regulation both pre- and post-market.

Medical devices may only be promoted and sold for the indications for which they are approved or cleared. In addition, even if the FDA has approved or cleared a product, it can take action affecting such product approvals or clearances if serious safety or other problems develop in the marketplace. Delays in obtaining clearances or approvals could adversely affect our ability to introduce new products or modifications to our existing products in a timely manner, which would delay or prevent commercial sales of our products. Additionally, the FDA and other regulatory authorities have broad enforcement powers. Regulatory enforcement or inquiries, or other increased scrutiny on us, could affect the perceived safety and efficacy of our products and dissuade our customers from using our products.

If we modify our FDA cleared devices, we may need to seek additional clearances or approvals, which, if not granted, would prevent us from selling our modified products.

Our Inogen One systems have received pre-market clearance under Section 510(k) of the FDCA. The modifications made to our Inogen One G2 and Inogen One G3 systems represent non-significant modifications to the original Inogen One system, have the same indications for use, and are covered under our initial Inogen One 510(k) clearance. Any modifications to a 510(k)-cleared device that could significantly affect its safety or effectiveness, or would constitute a major change in its intended use, manufacture, design, components, or technology requires the submission and clearance of a new 510(k) pre-market notification or, possibly, pre-market approval. The FDA requires every manufacturer to make this determination in the first instance, but the FDA may review any manufacturer’s decision. The FDA may not agree with our decisions regarding whether new clearances or approvals are necessary. We have modified some of our 510(k) cleared products, and have determined based on our review of the applicable FDA guidance that in certain instances new 510(k) clearances or pre-market approval are not required. If the FDA disagrees with our determination and requires us to submit new 510(k) notifications or pre-market approval for modifications to our previously cleared products for which we have concluded that new clearances or approvals are unnecessary, we may be required to cease marketing or to recall the modified product until we obtain clearance or approval, and we may be subject to significant regulatory fines or penalties.

Furthermore, the FDA’s ongoing review of the 510(k) program may make it more difficult for us to make modifications to our previously cleared products, either by imposing more strict requirements on when a manufacturer must submit a new 510(k) for a modification to a previously cleared product, or by applying more onerous review criteria to such submissions. Specifically, pursuant to the Food and Drug Administration Safety and Innovation Act, which was signed into law in July 2012, the FDA is obligated to prepare a report for Congress on the FDA’s approach for determining when a new 510(k) will be required for modifications or changes to a previously cleared device. After submitting this report, the FDA is expected to issue revised guidance to assist device manufacturers in making this determination. Until then, manufacturers may continue to adhere to the FDA’s 1997 guidance on this topic when making a determination as to whether or not a new 510(k) is required for a change or modification to a device, but the practical impact of the FDA’s continuing scrutiny of these issues remains unclear.

If we fail to comply with FDA or state regulatory requirements, we can be subject to enforcement action.

The regulations to which we are subject are complex and have become more stringent over time. Regulatory changes could result in restrictions on our ability to continue or expand our operations, higher than anticipated costs or lower than anticipated sales. Even after we have obtained the proper regulatory clearance or approval to market a product, we have ongoing responsibilities under FDA regulations. The FDA and state authorities have broad enforcement powers. Our failure to comply with applicable regulatory requirements could result in enforcement action by the FDA or state agencies, which may include any of the following sanctions:

Any of these sanctions could result in higher than anticipated costs or lower than anticipated sales and have a material adverse effect on our reputation, business, results of operations and financial condition.

A recall of our products, either voluntarily or at the direction of the FDA or another governmental authority, or the discovery of serious safety issues with our products that leads to corrective actions, could have a significant adverse impact on us.

Medical devices, such as our Inogen One systems, can experience performance problems in the field that require review and possible corrective action by us or the product manufacturer. We cannot provide assurance that component failures, manufacturing errors, design defects and/or labeling inadequacies, which could result in an unsafe condition or injury to the operator or the patient will not occur. The FDA and similar foreign governmental authorities have the authority to require the recall of commercialized products in the event of material deficiencies or defects in design or manufacture of a product or in the event that a product poses an unacceptable risk to health. Manufacturers may also, under their own initiative, recall a product if any material deficiency in a device is found or withdraw a product to improve device performance or for other reasons. A government-mandated or voluntary recall by us or one of our distributors could occur as a result of an unacceptable risk to health, component failures, manufacturing errors, design or labeling defects or other deficiencies and issues. Similar regulatory agencies in other countries have similar authority to recall devices because of material deficiencies or defects in design or manufacture that could endanger health. Any recall would divert management attention and financial resources, could cause the price of our stock to decline and expose us to product liability or other claims and harm our reputation with customers. A recall involving our Inogen One systems could be particularly harmful to our business, financial and operating results.

In addition, under the FDA’s medical device reporting regulations, we are required to report to the FDA any incident in which our product may have caused or contributed to a death or serious injury or in which our product malfunctioned and, if the malfunction were to recur, would likely cause or contribute to death or serious injury. Repeated product malfunctions may result in a voluntary or involuntary product recall. Depending on the corrective action we take to redress a product’s deficiencies or defects, the FDA may require, or we may decide, that we will need to obtain new approvals or clearances for the device before we may market or distribute the corrected device. Seeking such approvals or clearances may delay our ability to replace the recalled devices in a timely manner. Moreover, if we do not adequately address problems associated with our devices, we may face additional regulatory enforcement action, including FDA warning letters, product seizure, injunctions, administrative penalties, or civil or criminal fines. We may also be required to bear other costs or take other actions that may have a negative impact on our sales as well as face significant adverse publicity or regulatory consequences, which could harm our business, including our ability to market our products in the future.

Any adverse event involving our products, whether in the United States or abroad could result in future voluntary corrective actions, such as recalls or customer notifications, or agency action, such as inspection, mandatory recall or other enforcement action. Any corrective action, whether voluntary or involuntary, as well as defending ourselves in a lawsuit, will require the dedication of our time and capital, distract management from operating our business and may harm our reputation and financial results.

If we or our component manufacturers fail to comply with the FDA’s Quality System Regulation, our manufacturing operations could be interrupted, and our product sales and operating results could suffer.

We and our component manufacturers are required to comply with the FDA’s Quality System Regulation, or QSR, which covers the procedures and documentation of the design, testing, production, control, quality assurance, labeling, packaging, sterilization, storage and shipping of our devices. The FDA audits compliance with the QSR through periodic announced and unannounced inspections of manufacturing and other facilities. We and our component manufacturers have been, and anticipate in the future being, subject to such inspections. Although we believe our manufacturing facilities and those of our component manufacturers are in compliance with the QSR, we cannot provide assurance that any future inspection will not result in adverse findings. If our manufacturing facilities or those of any of our component manufacturers or suppliers are found to be in violation of applicable laws and regulations, or we or our manufacturers or suppliers fail to take satisfactory corrective action in response to an adverse inspection, the FDA could take enforcement action, including any of the following sanctions:

Any of these sanctions could adversely affect our business, financial conditions and operating results.

Outside the United States, our products and operations are also often required to comply with standards set by industrial standards bodies, such as the International Organization for Standardization, or ISO. Foreign regulatory bodies may evaluate our products or the testing that our products undergo against these standards. The specific standards, types of evaluation and scope of review differ among foreign regulatory bodies. If we fail to adequately comply with any of these standards, a foreign regulatory body may take adverse actions similar to those within the power of the FDA. Any such action may harm our reputation and could have an adverse effect on our business, results of operations and financial condition.

If we fail to obtain and maintain regulatory approval in foreign jurisdictions, our market opportunities will be limited.

Approximately 18.8% and 20.5% of our revenue was from sales outside of the United States for the three months ended March 31, 2014 and March 31, 2013, respectively. We sell our products in 43 countries outside of the United States through distributors or directly to large “house” accounts. In order to market our products in the European Union or other foreign jurisdictions, we must obtain and maintain separate regulatory approvals and comply with numerous and varying regulatory requirements. The approval procedure varies from country to country and can involve additional testing. The time required to obtain approval abroad may be longer than the time required to obtain FDA clearance. The foreign regulatory approval process includes many of the risks associated with obtaining FDA clearance and we may not obtain foreign regulatory approvals on a timely basis, if at all. FDA clearance does not ensure approval by regulatory authorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries. However, the failure to obtain clearance or approval in one jurisdiction may have a negative impact on our ability to obtain clearance or approval elsewhere. If we do not obtain or maintain necessary approvals to commercialize our products in markets outside the United States, it would negatively affect our overall market penetration.

We may be subject to fines, penalties or injunctions if we are determined to be promoting the use of our products for unapproved or “off-label” uses, resulting in damage to our reputation and business.

Our promotional materials and training methods must comply with the FDA and other applicable laws and regulations, including the prohibition of the promotion of a medical device for a use that has not been cleared or approved by the FDA. Use of a device outside its cleared or approved indications is known as “off-label” use. Physicians may use our products off-label, as the FDA does not restrict or regulate a physician’s choice of treatment within the practice of medicine. If the FDA determines that our promotional materials or training constitutes promotion of an off-label use, it could request that we modify our training or promotional materials or subject us to regulatory or enforcement actions, which could have an adverse impact on our reputation and financial results.

Failure to comply with the Federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, the Health Information Technology for Economic and Clinical Health Act, or HITECH Act, and implementing regulations (including the final omnibus rule published on January 25, 2013) affecting the transmission, security and privacy of health information could result in significant penalties.

Numerous federal and state laws and regulations, including HIPAA and the HITECH Act, govern the collection, dissemination, security, use and confidentiality of patient-identifiable health information. HIPAA and the HITECH Act require us to comply with standards for the use and disclosure of health information within our company and with third parties. The Privacy Standards and Security Standards under HIPAA establish a set of basic national privacy and security standards for the protection of individually identifiable health information by health plans, healthcare clearinghouses and certain healthcare providers, referred to as covered entities, and the business associates with whom such covered entities contract for services. Notably, whereas HIPAA previously directly regulated only these covered entities, the HITECH Act, which was signed into law as part of the stimulus package in February 2009, makes certain of HIPAA’s privacy and security standards also directly applicable to covered entities’ business associates. As a result, both covered entities and business associates are now subject to significant civil and criminal penalties for failure to comply with Privacy Standards and Security Standards.

HIPAA and the HITECH Act also include standards for common healthcare electronic transactions and code sets, such as claims information, plan eligibility, payment information and the use of electronic signatures, and privacy and electronic security of individually identifiable health information. Covered entities, such as healthcare providers, are required to conform to such transaction set standards pursuant to HIPAA.

HIPAA requires healthcare providers like us to develop and maintain policies and procedures with respect to protected health information that is used or disclosed, including the adoption of administrative, physical and technical safeguards to protect such information. The HITECH Act expands the notification requirement for breaches of patient-identifiable health information, restricts certain disclosures and sales of patient-identifiable health information and provides a tiered system for civil monetary penalties for HIPAA violations. The HITECH Act also increased the civil and criminal penalties that may be imposed against covered entities, business associates and possibly other persons and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorney fees and costs associated with pursuing federal civil actions. Additionally, certain states have adopted comparable privacy and security laws and regulations, some of which may be more stringent than HIPAA.

If we do not comply with existing or new laws and regulations related to patient health information, we could be subject to criminal or civil sanctions. New health information standards, whether implemented pursuant to HIPAA, the HITECH Act, congressional action or otherwise, could have a significant effect on the manner in which we handle healthcare related data and communicate with payors, and the cost of complying with these standards could be significant.

The 2013 final HITECH omnibus rule modifies the breach reporting standard in a manner that will likely make more data security incidents qualify as reportable breaches. Any liability from a failure to comply with the requirements of HIPAA or the HITECH Act could adversely affect our financial condition. The costs of complying with privacy and security related legal and regulatory requirements are burdensome and could have a material adverse effect on our results of operations. These new provisions, as modified, will be subject to interpretation by various courts and other governmental authorities, thus creating potentially complex compliance issues for us, as well as our clients and strategic partners. In addition, we are unable to predict what changes to the HIPAA Privacy Standards and Security Standards might be made in the future or how those changes could affect our business. Any new legislation or regulation in the area of privacy and security of personal information, including personal health information, could also adversely affect our business operations.

Regulations requiring the use of “standard transactions” for healthcare services issued under HIPAA may negatively impact our profitability and cash flows.

Pursuant to HIPAA, final regulations have been implemented to improve the efficiency and effectiveness of the healthcare system by facilitating the electronic exchange of information in certain financial and administrative transactions while protecting the privacy and security of the information exchanged.

The HIPAA transaction standards are complex, and subject to differences in interpretation by third-party payors. For instance, some third-party payors may interpret the standards to require us to provide certain types of information, including demographic information not usually provided to us by physicians. As a result of inconsistent application of transaction standards by third-party payors or our inability to obtain certain billing information not usually provided to us by physicians, we could face increased costs and complexity, a temporary disruption in accounts receivable and ongoing reductions in reimbursements and net revenue. In addition, requirements for additional standard transactions, such as claims attachments or use of a national provider identifier, could prove technically difficult, time-consuming or expensive to implement, all of which could harm our business.

If we fail to comply with state and federal fraud and above laws, including anti-kickback, false claims and anti-inducement laws, we could face substantial penalties and our business, operations, and financial condition could be adversely affected.

The federal anti-kickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration to induce or in return for purchasing, leasing, ordering, or arranging for the purchase, lease or order of any healthcare item or service reimbursable under Medicare, Medicaid, or other federal financed healthcare programs. Although there are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution, the exceptions and safe harbors are drawn narrowly, and any remuneration to or from a prescriber or purchaser of healthcare products or services may be subject to scrutiny if they do not qualify for an exception or safe harbor. Our practices may not in all cases meet all of the criteria for safe harbor protection from anti-kickback liability.

Federal false claims laws prohibit any person from knowingly presenting or causing to be presented a false claim for payment to the federal government, or knowingly making or causing to be made a false statement to get a false claim paid. The majority of states also have statutes or regulations similar to the federal anti-kickback law and false claims laws, which apply to items or services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of payor. These false claims statutes allow any person to bring suit in the name of the government alleging false and fraudulent claims presented to or paid by the government (or other violations of the statutes) and to share in any amounts paid by the entity to the government in fines or settlement. Such suits, known as qui tam actions, have increased significantly in the healthcare industry in recent years. Sanctions under these federal and state laws may include civil monetary penalties, exclusion of a manufacturer’s products from reimbursement under government programs, criminal fines and imprisonment. In addition, the recently enacted Patient Protection and Affordable Care Act, among other things, amends the intent requirement of the federal anti-kickback and criminal healthcare fraud statutes. A person or entity no longer needs to have actual knowledge of this statute or specific intent to violate it. In addition, the Patient Protection and Affordable Care Act provides that the government may assert that a claim including items or services resulting from a violation of the federal anti-kickback statute constitutes a false or fraudulent claim for purposes of the false claims statutes. Because of the breadth of these laws and the narrowness of the safe harbors and exceptions, it is possible that some of our business activities could be subject to challenge under one or more of such laws. Such a challenge, regardless of the outcome, could have a material adverse effect on our business, business relationships, reputation, financial condition and results of operations.

The Patient Protection and Affordable Care Act also imposes new reporting and disclosure requirements on device and drug manufacturers for any “transfer of value” made or distributed to prescribers and other healthcare providers. Device and drug manufacturers will also be required to report and disclose any investment interests held by physicians and their immediate family members during the preceding calendar year. Failure to submit required information may result in civil monetary penalties of up to an aggregate of $150,000 per year (and up to an aggregate of $1 million per year for “knowing failures”), for all payments, transfers of value or ownership or investment interests not reported in an annual submission. As of August 1, 2013, manufacturers are required to collect data, and they will be required to submit their first data reports to the Centers for Medicare & Medicaid Services by March 31, 2014 and by the 90th day of each calendar year thereafter.

In addition, there has been a recent trend of increased federal and state regulation of payments made to physicians. Certain states, mandate implementation of compliance programs and/or the tracking and reporting of gifts, compensation and other remuneration to physicians. The shifting compliance environment and the need to build and maintain robust and expandable systems to comply with different compliance and/or reporting requirements in multiple jurisdictions increase the possibility that a healthcare company many violate one or more of the requirements.

The Federal Civil Monetary Penalties Law prohibits the offering or giving of remuneration to a Medicare or Medicaid beneficiary that the person knows or should know is likely to influence the beneficiary’s selection of a particular supplier of items or services reimbursable by a federal or state governmental healthcare program. We sometimes offer customers various discounts and other financial incentives in connection with the sales of our products. While it is our intent to comply with all applicable laws, the government may find that our marketing activities violate the Civil Monetary Penalties Law. If we are found to be in noncompliance, we could be subject to civil money penalties of up to $10,000 for each wrongful act, assessment of three times the amount claimed for each item or service and exclusion from the federal or state healthcare programs.

The scope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform, especially in light of the lack of applicable precedent and regulations. If our operations are found to be in violation of any of the laws described above or any other government regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restricting of our operations. Any penalties, damages, fines, curtailment or restructuring or our operations could harm our ability to operate our business and our financial results. Any action against us for violation of these laws, even if we successfully defend against it, could cause us to incur significant legal expenses and divert our management’s attention from operation of our business. Moreover, achieving and sustaining compliance with applicable federal and state fraud laws may prove costly.

Foreign governments tend to impose strict price controls, which may adversely affect our future profitability.

We sell our products in 43 countries outside the United States through distributors or directly to large “house” accounts. In some foreign countries, particularly in the European Union, the pricing of medical devices is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to supply data that compares the cost-effectiveness of our Inogen One systems to other available oxygen therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, it may not be profitable to sell our products in certain foreign countries, which would negatively affect the long-term growth of our business.

Our business activities involve the use of hazardous materials, which require compliance with environmental and occupational safety laws regulating the use of such materials. If we violate these laws, we could be subject to significant fines, liabilities or other adverse consequences.

Our research and development programs as well as our manufacturing operations involve the controlled use of hazardous materials. Accordingly, we are subject to federal, state and local laws governing the use, handling and disposal of these materials. Although we believe that our safety procedures for handling and disposing of these materials comply in all material respects with the standards prescribed by state and federal regulations, we cannot completely eliminate the risk of accidental contamination or injury from these materials. In the event of an accident or failure to comply with environmental laws, we could be held liable for resulting damages, and any such liability could exceed our insurance coverage.

If we are unable to secure and maintain patent or other intellectual property protection for the intellectual property used in our products, we will lose a significant competitive advantage, which may adversely affect our future profitability.

Our commercial success depends, in part, on obtaining and maintaining patent and other intellectual property protection for the technologies used in our products. The patent positions of medical device companies, including ours, can be highly uncertain and involve complex and evolving legal and factual questions. Furthermore, we might in the future opt to license intellectual property from other parties. If we, or the other parties from whom we would license intellectual property, fail to obtain and maintain adequate patent or other intellectual property protection for intellectual property used in our products, or if any protection is reduced or eliminated, others could use the intellectual property used in our products, resulting in harm to our competitive business position. In addition, patent and other intellectual property protection may not:

Any of our patents may be challenged, invalidated, circumvented or rendered unenforceable. We cannot provide assurance that we will be successful should one or more of our patents be challenged for any reason. If our patent claims are rendered invalid or unenforceable, or narrowed in scope, the patent coverage afforded our products could be impaired, which could make our products less competitive.

As of March 31, 2014, we had six pending U.S. patent applications, 25 issued U.S. patents and one issued Canadian patent relating to the design and construction of our oxygen concentrators and our intelligent delivery technology. Subsequent to March 31, 2014, the Company was issued one other patent from their pending list. As of April 30, 2014, the Company now has 26 issued patents in the U.S. We cannot specify which of these patents individually or as a group will permit us to gain or maintain a competitive advantage. U.S. patents and patent applications may be subject to interference proceedings, and U.S. patents may be subject to re-examination inter partes review, post-grant review, and derivation proceedings in the U.S. Patent and Trademark Office. Foreign patents may be subject to opposition or comparable proceedings in the corresponding foreign patent offices. Any of these proceedings could result in loss of the patent or denial of the patent application, or loss or reduction in the scope of one or more of the claims of the patent or patent application. Changes in either patent laws or in interpretations of patent laws may also diminish the value of our intellectual property or narrow the scope of our protection. Interference, re-examination and opposition proceedings may be costly and time consuming, and we, or the other parties from whom we might potentially license intellectual property, may be unsuccessful in defending against such proceedings. Thus, any patents that we own or might license may provide limited or no protection against competitors. In addition, our pending patent applications and those we may file in the future may have claims narrowed during prosecution or may not result in patents being issued. Even if any of our pending or future applications are issued, they may not provide us with adequate protection or any competitive advantages. Our patents and patent applications cover particular aspects of our products. Other parties may develop and obtain patent protection for more effective technologies, designs or methods for oxygen therapy. If these developments were to occur, it would likely have an adverse effect on our sales. Our ability to develop additional patentable technology is also uncertain.

Non-payment or delay in payment of patent fees or annuities, whether intentional or unintentional, may also result in the loss of patents or patent rights important to our business. Many countries, including certain countries in Europe, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to other parties. In addition, many countries limit the enforceability of patents against other parties, including government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of the patent. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as do the laws of the United States, particularly in the field of medical products and procedures

Our products could infringe the intellectual property rights of others, which may lead to patent and other intellectual property litigation that could itself be costly, could result in the payment of substantial damages or royalties, prevent us from using technology that is essential to our products, and/or force us to discontinue selling our products.

The medical device industry in general has been characterized by extensive litigation and administrative proceedings regarding patent infringement and intellectual property rights. Our competitors hold a significant number of patents relating to oxygen therapy devices and products. From time to time, we have commenced litigation to enforce our intellectual property rights. For example, we have pursued litigation against Inova Labs Inc. for infringement of two of our patents seeking damages, injunctive relief, costs, and attorneys’ fees. An adverse decision in this action or in any other legal action could limit our ability to assert our intellectual property rights, limit the value of our technology or otherwise negatively impact our business, financial condition and results of operations.

Monitoring unauthorized use of our intellectual property is difficult and costly. Unauthorized use of our intellectual property may have occurred or may occur in the future. Although we have taken steps to minimize the risk of this occurring, any such failure to identify unauthorized use and otherwise adequately protect our intellectual property would adversely affect our business. Moreover, if we are required to commence litigation, whether as a plaintiff or defendant as has occurred with Inova Labs Inc., not only will this be time-consuming, but we will also be forced to incur significant costs and divert our attention and efforts of our employees, which could, in turn, result in lower revenue and higher expenses.

We cannot provide assurance that our products or methods do not infringe the patents or other intellectual property rights of third parties and if our business is successful, the possibility may increase that others will assert infringement claims against us.

Determining whether a product infringes a patent involves complex legal and factual issues, and the outcome of a patent litigation action is often uncertain. We have not conducted an extensive search of patents issued or assigned to other parties, including our competitors, and no assurance can be given that patents containing claims covering our products, parts of our products, technology or methods do not exist, have not been filed or could not be filed or issued. Because of the number of patents issued and patent applications filed in our technical areas, our competitors or other parties may assert that our products and the methods we employ in the use of our products are covered by U.S. or foreign patents held by them. In addition, because patent applications can take many years to issue and because publication schedules for pending applications vary by jurisdiction and some companies opt not to publish their patent applications, there may be applications now pending of which we are unaware and which may result in issued patents that our current or future products infringe. Also, because the claims of published patent applications can change between publication and patent grant, there may be published patent applications that may ultimately issue with claims that we infringe. There could also be existing patents that one or more of our products or parts may infringe and of which we are unaware. As the number of competitors in the market for oxygen products and as the number of patents issued in this area grows, the possibility of patent infringement claims against us increases. In certain situations, we may determine that it is in our best interests to voluntarily challenge a party’s products or patents in litigation or other proceedings, including patent interferences or re-examinations. As a result, we may become involved in unwanted litigation that could be costly, result in diversion of management’s attention, require us to pay damages and force us to discontinue selling our products.

Infringement and other intellectual property claims and proceedings brought against us, whether successful or not, could result in substantial costs and harm to our reputation. Such claims and proceedings can also distract and divert management and key personnel from other tasks important to the success of the business. We cannot be certain that we will successfully defend against allegations of infringement of patents and intellectual property rights of others. In the event that we become subject to a patent infringement or other intellectual property lawsuit and if the other party’s patents or other intellectual property were upheld as valid and enforceable and we were found to infringe the other party’s patents or violate the terms of a license to which we are a party, we could be required to do one or more of the following:

If we are unable to prevent unauthorized use or disclosure of trade secrets, unpatented know-how and other proprietary information, our ability to compete will be harmed.

We rely on a combination of trade secrets, copyrights, trademarks, confidentiality agreements and other contractual provisions and technical security measures to protect certain aspects of our technology, especially where we do not believe that patent protection is appropriate or obtainable. We require our employees and consultants to execute confidentiality agreements in connection with their employment or consulting relationships with us. We also require our employees and consultants to disclose and assign to us all inventions conceived during the term of their employment or engagement while using our property or that relate to our business. We also require our corporate partners, outside scientific collaborators and sponsored researchers, advisors and others with access to our confidential information to sign confidentiality agreements. We also have taken precautions to initiate reasonable safeguards to protect our information technology systems. However, these measures may not be adequate to safeguard our proprietary intellectual property and conflicts may, nonetheless, arise regarding ownership of inventions. Such conflicts may lead to the loss or impairment of our intellectual property or to expensive litigation to defend our rights against competitors who may be better funded and have superior resources. Our employees, consultants, contractors, outside clinical collaborators and other advisors may unintentionally or willfully disclose our confidential information to competitors. In addition, confidentiality agreements may be unenforceable or may not provide an adequate remedy in the event of unauthorized disclosure. Enforcing a claim that a third party illegally obtained and is using our trade secrets is expensive and time-consuming, and the outcome is unpredictable. Moreover, our competitors may independently develop equivalent knowledge, methods and know-how. Unauthorized parties may also attempt to copy or reverse engineer certain aspects of our products that we consider proprietary, and in such cases we could not assert any trade secret rights against such party. As a result, other parties may be able to use our proprietary technology or information, and our ability to compete in the market would be harmed.

We have registered the trademarks Inogen; Inogen One; Inogen One G2; Oxygenation; Live Life in Moments, not Minutes; Never Run Out of Oxygen; Oxygen Therapy on Your Terms; Oxygen. Anytime. Anywhere; Reclaim Your Independence; Intelligent Delivery Technology; and the Inogen design with the United States Patent and Trademark Office. We have applied with the United States Patent and Trademark Office to register the trademark Inogen at Home. We have registered the trademark Inogen in Australia, New Zealand, Canada, Chile, China, South Korea, Mexico, and in Europe (European Community registration). We have registered the trademark Inogen One in Australia, Canada, Chile, China, South Korea, Mexico, and in Europe (European Community registration). We have registered the trademark Satellite Conserver in Australia, Mexico, Canada, Chile, China and South Korea. We have applied for a European Community registration to register the trademark Inogen at Home.

We may be subject to damages resulting from claims that our employees or we have wrongfully used or disclosed alleged trade secrets of other companies.

Many of our employees were previously employed at other medical device companies focused on the development of oxygen therapy products, including our competitors. Although no claims against us are currently pending, we may be subject to claims that these employees or we have inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers. Litigation may be necessary to defend against these claims. If we fail in defending such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights. Even if we are successful in defending against these claims, litigation could result in substantial costs, damage to our reputation and be a distraction to management.

We will incur increased costs as a result of operating as a public company and our management will be required to devote substantial time to new compliance initiatives and corporate governance practices.

As a public company, and increasingly after we are no longer an “emerging growth company,” we will incur significant legal, accounting and other expenses that we did not incur as a private company. In addition, the Sarbanes-Oxley Act and rules subsequently implemented by the SEC and the NASDAQ Global Select Market impose numerous requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Also, the Securities Exchange Act of 1934, as amended, or the Exchange Act, requires, among other things, that we file annual, quarterly and current reports with respect to our business and operating results. Our management and other personnel will need to devote a substantial amount of time to compliance with these laws and regulations. These requirements have increased and will continue to increase our legal, accounting, and financial compliance costs and have made and will continue to make some activities more time consuming and costly. For example, we expect these rules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to incur substantial costs to maintain the same or similar coverage. These rules and regulations could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors or our board committees or as executive officers.

Overall, we estimate that our incremental costs resulting from operating as a public company, including compliance with these rules and regulations, may be between $1.5 million and $3.0 million per year. However, these rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices.

The Sarbanes-Oxley Act requires, among other things, that we assess the effectiveness of our internal control over financial reporting annually and the effectiveness of our disclosure controls and procedures quarterly. In particular, Section 404(a) of the Sarbanes-Oxley Act, or Section 404(a), will require us to perform system and process evaluation and testing of our internal control over financial reporting to allow management to report on the effectiveness of our internal control over financial reporting. Section 404(b) of Sarbanes-Oxley Act, or Section 404(b), also requires our independent registered public accounting firm to attest to the effectiveness of our internal control over financial reporting. As an “emerging growth company” we expect to avail ourselves of the exemption from the requirement that our independent registered public accounting firm attest to the effectiveness of our internal control over financial reporting under Section 404(b). However, we may no longer avail ourselves of this exemption when we are no longer an “emerging growth company.” When our independent registered public accounting firm is required to undertake an assessment of our internal control over financial reporting, the cost of our compliance with Section 404(b) will correspondingly increase. Our compliance with applicable provisions of Section 404 will require that we incur substantial accounting expense and expend significant management time on compliance-related issues as we implement additional corporate governance practices and comply with reporting requirements.

Furthermore, investor perceptions of our company may suffer if deficiencies are found, and this could cause a decline in the market price of our stock. Irrespective of compliance with Section 404, any failure of our internal control over financial reporting could have a material adverse effect on our stated operating results and harm our reputation. If we are unable to implement these requirements effectively or efficiently, it could harm our operations, financial reporting, or financial results and could result in an adverse opinion on our internal controls from our independent registered public accounting firm.

If we fail to maintain effective internal control over financial reporting in the future, the accuracy and timing of our financial reporting may be adversely affected.

No material weaknesses in internal control over financial reporting were identified in connection with our 2013 audit. However, our management and independent registered public accounting firm did not perform an evaluation of our internal control over financial reporting during any period in accordance with the provisions of the Sarbanes-Oxley Act. Had we and our independent registered public accounting firm performed an evaluation of our internal control over financial reporting in accordance with the provisions of the Sarbanes-Oxley Act, additional control deficiencies amounting to significant deficiencies or material weaknesses may have been identified. We cannot be certain as to when we will be able to implement the requirements of Section 404 of the Sarbanes-Oxley Act. If we fail to implement the requirements of Section 404 in a timely manner, we might be subject to sanctions or investigation by regulatory agencies such as the SEC. In addition, failure to comply with Section 404 or the report by us of a significant deficiency or material weakness may cause investors to lose confidence in our financial statements, and the trading price of our common stock may decline. If we fail to remedy any significant deficiency or material weakness, our financial statements may be inaccurate, our access to the capital markets may be restricted and the trading price of our ordinary shares may suffer.

We are an “emerging growth company” and the reduced disclosure requirements applicable to emerging growth companies may make our common stock less attractive to investors.

We are an “emerging growth company,” as defined in the 2012 Jumpstart Our Business Startups (JOBS) Act, and we may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, reduced financial disclosure obligations, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and any golden parachute payments not previously approved. We may take advantage of these provisions for up to five years or such earlier time that we are no longer an emerging growth company. We would cease to be an emerging growth company upon the earliest to occur of: the last day of the fiscal year in which we have more than $1.0 billion in annual revenue; the date we qualify as a large accelerated filer, with at least $700 million of equity securities held by non-affiliates; the issuance, in any three-year period, by us of more than $1.0 billion in non-convertible debt securities; and the last day of the fiscal year ending after the fifth anniversary of our initial public offering. We may choose to take advantage of some but not all of these reduced reporting burdens. If we take advantage of any of these reduced reporting burdens in future filings, the information that we provide our security holders may be different than you might get from other public companies in which you hold equity interests. We cannot predict if investors will find our common stock less attractive because we may rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

We expect that our stock price will fluctuate significantly, and you may have difficulty selling your shares.

Prior to our initial public offering, there has been no public market for shares of our common stock. We cannot predict the extent to which investor interest in our company will lead to the development of an active trading market on the NASDAQ Global Select Market or otherwise or how liquid that market might become. If an active trading market does not develop, you may have difficulty selling any of our shares of common stock that you buy. In addition, the trading price of our common stock may be highly volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control. These factors include:

The stock market in general and market prices for the securities of technology-based companies like ours in particular, have from time to time experienced volatility that often has been unrelated to the operating performance of the underlying companies. A certain degree of stock price volatility can be attributed to being a newly public company. These broad market and industry fluctuations may adversely affect the market price of our common stock, regardless of our operating performance. In several recent situations where the market price of a stock has been volatile, holders of that stock have instituted securities class action litigation against the Company that issued the stock. If any of our stockholders were to bring a lawsuit against us, the defense and disposition of the lawsuit could be costly and divert the time and attention of our management and harm our operating results.

If securities or industry analysts do not publish research or publish unfavorable research about our business, our stock price and trading volume could decline.

The trading market for our common stock will rely in part on the research and reports that equity research analysts publish about us and our business. We will not have any control of the analysts or the content and opinions included in their reports. The price of our stock could decline if one or more equity research analysts downgrade our stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of our company or fails to publish reports on us regularly, demand for our stock could decrease, which in turn could cause our stock price or trading volume to decline.

If stockholders holding shares of our common stock purchased prior to our public offering sell, or indicate an intention to sell, substantial amounts of their common stock in the public market the trading price of our common stock could decline. As of March 31, 2014 we had outstanding a total of 18,151,551 shares of common stock (including 3,979 of stock options which were exercised, but stock certificates were not yet issued) of which only the 4,411,763 shares of common stock sold by us and the selling stockholders in our initial public offering are freely tradable, without restriction, in the public market. Each of our directors and officers, and certain of our stockholders, has entered into lock-up agreements with the underwriter of our initial public offering that restrict their ability to sell or transfer their shares. The lock-up agreements pertaining to our public offering are in effect through August 12, 2014. Our underwriters, however, may, in their sole discretion, permit our officers, directors and other current stockholders who are subject to the contractual lock-up to sell shares prior to the expiration of the lock-up agreements. After the lock-up agreements expire, based on shares outstanding as of March 31, 2014, up to an additional 13,739,788 shares of common stock will be eligible for sale in the public market, 3,013,219 of which are held by directors and executive officers and will be subject to volume limitations under Rule 144 under the Securities Act of 1933, as amended, or the Securities Act, and various vesting agreements. In addition 1,593,049 shares of common stock that are issuable upon exercise of outstanding options as of March 31, 2014 will become eligible for sale in the public market to the extent permitted by the provisions of various vesting agreements, the lock-up agreements and Rules 144 and 701 under the Securities Act. If these additional shares are sold, or if it is perceived that they will be sold, in the public market, the trading price of our common stock could decline.

Our directors, executive officers and principal stockholders will continue to have substantial control over us and could limit your ability to influence the outcome of key transactions, including changes of control.

As of March 31, 2014, our executive officers, directors and stockholders who owned more than 5% of our outstanding common stock and their respective affiliates beneficially owned or controlled approximately 69.9% of the outstanding shares of our common stock, assuming no exercise of the underwriters’ option to purchase additional shares which was granted by certain of our selling stockholders in connection with our initial public offering. Accordingly, these executive officers, directors and stockholders who owned more than 5% of our outstanding common stock before this offering and their respective affiliates, acting as a group, will have substantial influence over the outcome of corporate actions requiring stockholder approval, including the election of directors, any merger, consolidation or sale of all or substantially all of our assets or any other significant corporate transactions. These stockholders may also delay or prevent a change of control of us, even if such a change of control would benefit our other stockholders. The significant concentration of stock ownership may adversely affect the trading price of our common stock due to investors’ perception that conflicts of interest may exist or arise.

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management and limit the market price of our common stock.

Provisions in our certificate of incorporation and bylaws may have the effect of delaying or preventing a change of control or changes in our management. Our amended and restated certificate of incorporation and amended and restated bylaws include provisions that:

These provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, which is responsible for appointing the members of our management. In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which limits the ability of stockholders owning in excess of 15% of our outstanding voting stock to merge or combine with us.

We have broad discretion in the use of the net proceeds from our initial public offering and may not use them effectively.

We have broad discretion in the application of the net proceeds from our initial public offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. We intend to use approximately $15 million of the net proceeds from our initial public offering for investments in rental assets; approximately $5 million of the net proceeds for sales and marketing activities, including expansion of our sales force to support the ongoing commercialization of our products; approximately $3 million of the net proceeds for research and product development activities; approximately $11 million of the net proceeds for facilities improvements or expansions and the purchase of manufacturing and other equipment; and the remainder of the net proceeds for working capital and other general corporate purposes. We may also use a portion of our net proceeds to acquire and invest in complementary products, technologies or businesses; however, we currently have no agreements or commitments to complete any such transaction. We have not allocated these net proceeds for any specific purposes. We might not be able to yield a significant return, if any, on any investment of these net proceeds. Stockholders will not have the opportunity to influence our management’s decisions on how to use the net proceeds, and our failure to apply these funds effectively could have a material adverse effect on our business and cause the price of our common stock to decline.

We have never paid dividends on our capital stock, and we do not anticipate paying any cash dividends in the foreseeable future.

We have paid no cash dividends on any of our classes of capital stock to date, have contractual restrictions against paying cash dividends and currently intend to retain our future earnings to fund the development and growth of our business. As a result, capital appreciation, if any, of our common stock will be your sole source of gain for the foreseeable future.

Between January 1, 2014 and March 31, 2014, we sold securities in transactions that were not registered under the Securities Act as set forth below.

Between January 1, 2014 and February 18, 2014 (the date of the filing of our registration statement on Form S-8, File No. 333-194016), we issued and sold an aggregate of 2,093 shares of common stock to officers, employees and consultants upon the exercise of options, at exercise prices ranging from $0.60 to $8.70 per share, for an aggregate exercise price of $5,235, pursuant to our 2002 Stock Incentive Plan.

Between January 1, 2014 and March 31, 2014, we issued and sold an aggregate of 72,316 shares of common stock warrants to investors upon the exercise of warrants at an exercise price of $0.30, for an aggregate exercise price of $21,695, we issued and sold an aggregate of 11,459 shares of Series C redeemable convertible preferred stock warrants (of which 631 shares were exercised via a cashless exercise into 228 shares of common stock) at an exercise price of $17.58 for an aggregate exercise price of $195,033 and we issued and sold 11,415 shares of Series D redeemable convertible preferred stock warrants at an exercise price of $21.90 for an aggregate exercise price of $249,989.

None of the foregoing transactions involved any underwriters, underwriting discounts or commissions, or any public offering, and each transaction was deemed to be exempt from the registration requirements of the Securities Act, in reliance on (i) Section 4(2) of the Securities Act (or Regulation D promulgated thereunder) as transactions not involving a public offering, (ii) Rule 701 promulgated under the Securities Act as transactions pursuant to compensatory benefit plans or contracts relating to compensation as provided under such rule, or (iii) Regulation S promulgated under the Securities Act as transactions made outside of the United States. The recipients of the securities in each of these transactions represented their intentions to acquire the securities for investment only and not with a view to or for sale in connection with any distribution thereof, and appropriate legends were placed upon the stock certificates issued in these transactions. All recipients had adequate access, through their relationships with us, to information about us. The sales of these securities were made without any general solicitation or advertising.

On February 20, 2014, our Registration Statement on Form S-1, as amended (Reg. No. 333- 192605) was declared effective in connection with the IPO of our common stock, pursuant to which we sold 3,529,411 shares at a price to the public of $16.00 per share. Additionally, the selling stockholders sold 981,902 shares of common stock (882,352 upon the IPO, and 99,550 of which were sold pursuant to a 30-day option granted to the underwriters). The offering closed on February 20, 2014, as a result of which we received net proceeds of approximately $52.5 million after underwriting discounts of approximately $3.9 million, but before offering expenses of approximately $2.8 million. We did not receive any proceeds from the shares sold by the selling stockholders. J.P. Morgan acted as sole book-running manager for the offering, Leerink Partners acted as lead manager, and William Blair and Stifel acted as co-managers. No payments for such expenses were made directly or indirectly to (i) any of our officers or directors or their associates, (ii) any persons owning 10% or more of any class of our equity securities, or (iii) any of our affiliates. There has been no material change in the planned use of proceeds from our initial public offering as described in our final prospectus filed with the SEC pursuant to Rule 424(b) under the Securities Act on Use of Proceeds from Initial Public Offering of Common Stock.

Pursuant to the requirements of the Securities Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Delaware		33-0989359
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

326 Bollay Drive Goleta, California		93117
(Address of principal executive offices)		(Zip Code)

Title of each class		Name of each exchange on which registered
Common Stock, $0.001 par value		The NASDAQ Global Select Market

Large accelerated filer	¨	Accelerated filer	¨

Non-accelerated filer	x (Do not check if a smaller reporting company)	Smaller reporting company	¨

	Part I – Financial Information	Page
Item 1.	Financial Statements (Unaudited)	3
	Balance Sheets as of March 31, 2014 and December 31, 2013	3
	Statements of Operations for the Three Months Ended March 31, 2014 and March 31, 2013	5
	Statements of Redeemable Convertible Preferred Stock for the Three Months Ended March 31, 2014 and Year Ended December 31, 2013	6
	Statements of Stockholders’ Equity (Deficit) for the Three Months Ended March 31, 2014 and Year-Ended December 31, 2013	7
	Statements of Cash Flows for the Three Months ended March 31, 2014 and March 31, 2013	8
	Condensed Notes to the Financial Statements	9
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	26
Item 3.	Quantitative and Qualitative Disclosures about Market Risk	35
Item 4.	Controls and Procedures	36
	Part II – Other Information
Item 1.	Legal Proceedings	37
Item 1A.	Risk Factors	37
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	59
Item 6.	Exhibits	61

Level input		Input definition
Level 1		Inputs are unadjusted, quoted prices for identical assets or liabilities in active markets at the measurement date.

Level 2		Inputs, other than quoted prices included in Level 1 that are observable for the asset or liability through corroboration with market data at the measurement date.

Level 3		Unobservable inputs that reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date.

	Warrant liability
Balance as of December 31, 2012	$	164
Fair value of preferred stock warrants exercised		(31	)
Change in fair value		(20	)
Balance as of March 31, 2013	$	113

	Warrant liability
Balance as of December 31, 2013	$	260
Fair value of preferred stock warrants exercised		(148	)
Change in fair value		(36	)
Reclassification of liability to additional paid in capital		(76	)
Balance as of March 31, 2014	$	—

Rental equipment		1.5-5 years
Manufacturing equipment and tooling		5 years
Computer equipment and software		3 years
Furniture and equipment		3-5 years
Leasehold improvements		Shorter of 3-10 years or life of underlying lease

March 31, 2014	Average estimated useful lives (in years)	Gross carrying amount		Accumulated amortization		Net amount
Licenses	10	$	185	$	68	$	117
Patents	5		723		680		43
Commercial and websites	2		242		57		185
Total		$	1,150	$	805	$	345

December 31, 2013	Average estimated useful lives (in years)	Gross carrying amount		Accumulated amortization		Net amount
Licenses	10	$	185	$	63	$	122
Patents	5		723		662		61
Commercial	2		73		41		32
Total		$	981	$	766	$	215

	March 31, 2014
Remaining 9 months of 2014	$	3,754
2015		3,378
2016		2,057
Total	$	9,189

	Three Months Ended March 31,
	2014			2013
Product warranty liability at beginning of period	$	809		$	447
Accruals for warranties issued		208			88
Adjustments related to preexisting warranties (including changes in estimates)		138			244
Settlements made (in cash or in kind)		(234	)		(85	)
Product warranty liability at end of period	$	921		$	694

As of March 31, 2014
Series	A
Shares authorized		100,000
Share issued		66,666
Shares converted		(66,666	)
Shares outstanding		—

As of December 31, 2013
Series	A
Shares authorized		100,000
Share issued		66,666
Par value	$	0.001
Conversion rate		1.01706
Liquidation preference per share	$	3.750
Dividend rate		5	%
Issue date	May 2002

Series	Options			Price per share		Weighted-average exercise price		Remaining weighted-average contractual terms (in years)		Per share average intrinsic value
Outstanding as of December 31, 2013		2,328,675		$0.60 - $8.70		$	1.94		7.04	$	10.23
Granted		—			—		—
Exercised		(8,975	)	$0.60 - $8.70			1.29
Forfeited		(335	)	$0.60 - $0.75			0.69
Expired		(4,799	)	$0.60 - $8.37			1.09
Outstanding as of March 31, 2014		2,314,566		$0.60 - $8.70		$	1.94		6.80	$	14.62

	Number of		Exercise		Expiration
Security	warrants		price/share		date
Former Series E redeemable convertible preferred stock warrants		4,222	$	9.612	2017
Common stock		161,295		0.300	2017-2019
		165,517

	March 31, 2014
Remaining 9 months of 2014	$	626
2015		732
2016		335
2017		327
2018		315
Thereafter		313
	$	2,648

Exhibit Number		Description

31.1		Certification Pursuant to Exchange Act Rules 13a – 14(a) and 15d – 14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 of Chief Executive Officer

31.2		Certification Pursuant to Exchange Act Rules 13a – 14(a) and 15d – 14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 of Chief Financial Officer

32.1(1)		Certification Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 of Chief Executive Officer

32.2(1)		Certification Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 of Chief Financial Officer

101.INS(2)		XBRL Instance Document

101.SCH(2)		XBRL Taxonomy Extension Schema Document

101.CAL(2)		XBRL Taxonomy Extension Calculation Linkbase Document

101.LAB(2)		XBRL Taxonomy Extension Label Linkbase Document

101.PRE(2)		XBRL Taxonomy Extension Presentation Linkbase Document

101.DEF(2)		XBRL Taxonomy Extension Definition Document

		inogen, inc.

Dated:	May 13, 2014	By:	/s/ Raymond Huggenberger
			Raymond Huggenberger
			President and Chief Executive Officer

Dated:	May 13, 2014	By:	/s/ Alison Bauerlein
			Alison Bauerlein
			Chief Financial Officer Executive Vice President, Finance Secretary and Treasurer (principal financial and accounting officer)