Balance Sheet Components (Accrued Liabilities) (Details) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Balance Sheet Related Disclosures [Abstract] | ||
| Clinical trials | $ 2,152 | $ 1,666 |
| Compensation and related expenses | 832 | 993 |
| Professional services | 194 | 319 |
| Interest expense and other | 77 | 155 |
| Total accrued liabilities | $ 3,255 | $ 3,133 |