Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
Tax benefit at federal statutory rate	$ (8,211)	$ (10,225)	$ (9,941)
State taxes, net of federal benefit	(15,350)	(3,394)	(4,985)
Revaluation of deferred tax items due to tax rate change (state)	0	(404)	0
Section 162(m) limitations	9,008	6,682	2,944
Stock-based compensation	(49,020)	(12,665)	(14,728)
Nondeductible permanent items	1,422	2,001	1,103
Tax benefit of federal R&D credit	(3,694)	(3,509)	(3,141)
Valuation allowance	63,369	21,981	29,068
Other	1,106	(758)	(181)
Total income tax provision	$ (1,370)	$ (291)	$ 139