Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands |
Jun. 30, 2016 |
Dec. 31, 2015 |
Jun. 30, 2015 |
Dec. 31, 2014 |
---|---|---|---|---|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
Cash and cash equivalents | $ 8,484 | $ 36,079 | $ 53,494 | $ 54,059 |
Total | 8,484 | 36,079 | ||
Warrant liability | 13 | 115 | ||
Total | 13 | 115 | ||
Active Markets (Level 1) | ||||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
Cash and cash equivalents | 8,484 | 36,079 | ||
Total | 8,484 | 36,079 | ||
Unobservable Inputs (Level 3) | ||||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
Warrant liability | 13 | 115 | ||
Total | $ 13 | $ 115 |