Fair Value Measurement - Summary of Fair Values of Assets and Liabilities Measured at Fair Value On Recurring and NonRecurring Basis (Details) - USD ($) $ in Thousands |
Mar. 31, 2017 |
Dec. 31, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|---|
| Cash and cash equivalents | $ 1,555 | $ 3,640 | $ 10,242 | $ 9,276 |
| Total assets | 122,518 | 124,883 | ||
| Warrants potentially settleable in cash | 905 | 1,476 | ||
| Total liabilities | 22,535 | 22,564 | ||
| Quoted Prices in Active Markets Level 1 [Member] | ||||
| Cash and cash equivalents | 1,555 | 3,640 | ||
| Total assets | 1,555 | 3,640 | ||
| Warrants potentially settleable in cash | ||||
| Total liabilities | ||||
| Significant Other Observable Inputs Level 2 [Member] | ||||
| Cash and cash equivalents | ||||
| Total assets | ||||
| Warrants potentially settleable in cash | ||||
| Total liabilities | ||||
| Unobservable Inputs Level 3 [Member] | ||||
| Cash and cash equivalents | ||||
| Total assets | ||||
| Warrants potentially settleable in cash | 905 | 1,476 | ||
| Total liabilities | $ 905 | $ 1,476 |