Significant Balance Sheet Components - Payables (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Accrued commissions	$ 4,181	$ 6,199
Accrued stock settled bonus	4,714
Accrued vacation	512	3,589
Employee stock purchase plan liability	2,329	4,280
Other accrued payroll-related expenses	2,483	2,231
Liability for early exercised stock options	48	294
Other accrued liabilities	4,929	4,576
Total accrued expenses	$ 19,196	$ 21,169