5. Commitments and contingencies

Leases

The Company leases its offices and certain equipment under operating leases that expire through January 2022. At March 31, 2015, the minimum aggregate payments due under non-cancelable leases are summarized as follows:

Rent expense of $220 and $207, for the three months ended March 31, 2015 and March 31, 2014, respectively, was included in the accompanying Statements of Operations.

Warranty obligation

The following table identifies the changes in the Company’s aggregate product warranty liabilities for the three and twelve month periods ended March 31, 2015 and December 31, 2014, respectively:

Legislation and HIPAA

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 it 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.

Legal proceedings

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 the Company’s 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. The Company 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. The Company 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 the Company’s motion to dismiss the Defendant’s inequitable conduct counterclaim.

Securities class action lawsuit

On March 13 and March 19, 2015, plaintiffs Brad Christi and Roger D. Holford each filed, respectively, a lawsuit against Inogen, Raymond Huggenberger, Inogen’s President and Chief Executive Officer, and Alison Bauerlein, Inogen’s Executive Vice President and Chief Financial Officer, in the United States District Court for the Central District of California on behalf of a purported class of purchasers of our securities between November 12, 2014 and March 11, 2015. The complaints allege that Inogen, Mr. Huggenberger and Ms. Bauerlein violated Section 10(b) of the Securities Exchange Act of 1934, as amended and Rule 10b-5 promulgated thereunder, and that Mr. Huggenberger and Ms. Bauerlein violated Section 20(a) of the Securities Exchange Act of 1934.  Specifically, the complaints allege that during the purported class period our financial statements and disclosures concerning internal controls over financial reporting were materially false and misleading.  The complaints seek compensatory damages in an unspecified amount, costs and expenses, including attorneys’ fees and expert fees, prejudgment and post-judgment interest and such other relief as the court deems proper.  The deadline for motions for appointment as lead plaintiff is May 12, 2015.  On May 7, 2015, plaintiff Roger D. Holford filed a notice of voluntary dismissal without prejudice pursuant to Federal Rule of Civil Procedure Rule 41(a)(1)(A) in the second filed action.  We intend to vigorously defend ourselves against these allegations.  We are currently unable to predict the outcome of the first filed lawsuit and therefore cannot determine the likelihood of loss nor estimate a range of possible loss.

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.