Significant Balance Sheet Components - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Expenses [Abstract]
Accrued commissions	$ 4,810	$ 4,398
Accrued stock-settled bonus	6,875	9,355
Employee Stock Purchase Plan liability	2,187	1,923
Other accrued payroll-related expenses	2,839	3,630
Accrued royalties	2,386	3,596
Other accrued liabilities	5,695	4,445
Total accrued expenses	$ 24,792	$ 27,347