Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of the Federal Statutory Income Tax Rate to the Effective Income Tax Rate (Details)

v2.4.1.9
Income Taxes - Reconciliation of the Federal Statutory Income Tax Rate to the Effective Income Tax Rate (Details)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]      
U.S. Statutory rate 34.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate 34.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate 34.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
State income taxes (net of federal benefit) 2.47%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes 5.48%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes 4.53%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
Nondeductible expenses 1.39%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense 2.54%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense (2.77%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense
Remeasured deferred for state rate change (0.25%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingenciesStateAndLocal (8.25%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingenciesStateAndLocal (137.26%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingenciesStateAndLocal
Change in valuation allowance (12.16%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance (595.34%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance 105.55%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance
R&D credit (net of reserve) (3.49%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch    
Expiration of net operating losses 8.09%ingn_EffectiveIncomeTaxRateReconciliationNetOperatingLossExpiration    
Other 2.04%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments 0.58%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments (1.02%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
Effective income tax rate 32.09%us-gaap_EffectiveIncomeTaxRateContinuingOperations (560.99%)us-gaap_EffectiveIncomeTaxRateContinuingOperations 3.03%us-gaap_EffectiveIncomeTaxRateContinuingOperations