Balance Sheet Components (Accrued liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accrued and other current liabilities
Accrued clinical trial and research and development expenses	$ 159	$ 119
Audit, consulting and legal fees	2,073	803
Payroll and related expenses	2,390	2,592
Accrued commission	2,049	1,222
Warrant liability	178	99
Other	1,513	1,672
Total	$ 8,362	$ 6,507