Balance Sheet Components - Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Prepaid and Other Current Assets | ||
| Interest Receivable | $ 365 | |
| Prepaid research and development manufacturing expenses | $ 722 | |
| Tenant improvement allowance receivable | 347 | |
| Other | 772 | 208 |
| Total of prepaid and other current assets | $ 1,137 | $ 1,277 |