Balance Sheet Components - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued vacation	$ 3,809	$ 2,825
Accrued payroll and related expenses	19,156	18,188
Accrued ESPP Contributions	417	373
Accrued professional services fees	2,846	1,249
Claims payable	2,802	2,374
Other	3,556	1,679
Total accrued liabilities	$ 32,586	$ 26,688