Financial Instruments - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Warrant liabilities | $ 1,004 | $ 649 |
| Fair Value Measurements, Recurring Basis [Member] | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Warrant liabilities | 1,004 | 649 |
| Fair Value Measurements, Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Warrant liabilities | $ 1,004 | $ 649 |