Significant Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 22,683	$ 23,426
Accumulated depreciation and amortization	(17,879)	(16,380)
Total property and equipment-net	4,804	7,046
Computers and appliances
Property Plant And Equipment [Line Items]
Total property and equipment	13,300	13,517
Purchased software
Property Plant And Equipment [Line Items]
Total property and equipment	4,235	4,711
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	1,745	1,695
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 3,403	$ 3,503