Fair Value Measurements - Summary of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Cash and cash equivalents | $ 6,870 | $ 777 |
| Total assets | 6,870 | 777 |
| Warrants potentially settleable in cash | 288 | 569 |
| Total liabilities | 288 | 569 |
| Quoted Prices in Active Markets Level 1 [Member] | ||
| Cash and cash equivalents | 6,870 | 777 |
| Total assets | 6,870 | 777 |
| 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 | 288 | 569 |
| Total liabilities | $ 288 | $ 569 |