Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Computation of Earnings Per Share (Details)

v2.4.1.9
Summary of Significant Accounting Policies - Computation of Earnings Per Share (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Dec. 31, 2009
Numerator—basic and diluted:        
Net income $ 1,572us-gaap_NetIncomeLoss $ 888us-gaap_NetIncomeLoss $ 6,800us-gaap_NetIncomeLoss $ 2,600us-gaap_NetIncomeLoss
Less deemed dividend on redeemable convertible preferred stock   (987)ingn_DeemedDividendOnRedeemableConvertiblePreferredStock    
Net income (loss) attributable to common stockholders - basic $ 1,572ingn_NetIncomeLossAvailableToCommonStockholdersBasicNetOfUndistributedEarningsToPreferredStock $ (99)ingn_NetIncomeLossAvailableToCommonStockholdersBasicNetOfUndistributedEarningsToPreferredStock    
Denominator:        
Weighted-average common shares - basic common stock 19,167,585us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 9,437,525us-gaap_WeightedAverageNumberOfSharesOutstandingBasic    
Weighted-average common shares - diluted common stock 20,562,040us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 9,437,525us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding    
Net income (loss) per share - basic common stock $ 0.08us-gaap_EarningsPerShareBasic $ (0.01)us-gaap_EarningsPerShareBasic    
Net income (loss) per share - diluted common stock $ 0.08us-gaap_EarningsPerShareDiluted $ (0.01)us-gaap_EarningsPerShareDiluted    
Shares excluded from diluted net income (loss):        
Shares excluded from diluted net income (loss) 110,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 25,630us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount    
Weighted-average number of shares used in calculating net income (loss) per share attributable to common stockholders:        
Weighted-average common shares - basic common stock 19,167,585us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 9,437,525us-gaap_WeightedAverageNumberOfSharesOutstandingBasic    
Warrants 9,649us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants      
Stock options 1,384,806us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements      
Weighted-average common shares - diluted common stock 20,562,040us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 9,437,525us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding    
Stock Options        
Shares excluded from diluted net income (loss):        
Shares excluded from diluted net income (loss) 110,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_StockOptionMember
25,630us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_StockOptionMember