Significant Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 16,987	$ 16,513
Accumulated depreciation and amortization	(11,798)	(11,010)
Total property and equipment-net	5,189	5,503
Computers and appliances
Property Plant And Equipment [Line Items]
Property and equipment, gross	10,141	9,754
Purchased software
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,361	2,297
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,483	1,477
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 3,002	$ 2,985