Balance Sheet Components (Accrued liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accrued and other current liabilities
Accrued clinical trial and research and development expenses	$ 108	$ 215
Audit, consulting and legal fees	2,151	1,208
Payroll and related expenses	2,153	2,494
Accrued commission	2,143	1,960
Warrant liability	66	60
Other	795	1,022
Total	$ 7,416	$ 6,959