Balance Sheet Components (Accrued liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accrued and other current liabilities
Accrued clinical trial and research and development expenses	$ 121	$ 215
Audit, consulting and legal fees	1,702	1,208
Payroll and related expenses	1,654	2,494
Accrued commission	1,549	1,960
Warrant liability	75	60
Other	647	1,022
Total	$ 5,748	$ 6,959