Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accrued liabilities
Accrued payroll-related expenses	$ 1,075	$ 1,045
Deferred licensing revenue	42	229
Deferred rent	221	248
Accrued sales commissions payable to sales representatives	136	193
Other	616	96
Total accrued liabilities	$ 2,090	$ 1,811