Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Summary of Fair Value Liabilities Measured on Recurring Basis (Details)

v2.4.1.9
Summary of Significant Accounting Policies - Summary of Fair Value Liabilities Measured on Recurring Basis (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Preferred stock warrant liability $ 0ingn_PreferredStockWarrantLiability $ 260ingn_PreferredStockWarrantLiability
Total liabilities   260us-gaap_LiabilitiesFairValueDisclosure
Level 3    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Preferred stock warrant liability   260ingn_PreferredStockWarrantLiability
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Total liabilities   $ 260us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member