Income Taxes - Effective Tax Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effective tax rates differing from U.S. federal statutory rate
U.S. Federal taxes (benefit) at statutory rate	$ (91,251)	$ (114,832)	$ (98,931)
State tax expense	(13,492)	(21,676)	(29,206)
Research and development credits	(10,837)	(7,024)	(9,193)
Stock-based compensation	(6,422)	3,949	(46,128)
Foreign tax	(106)	332	167
Nondeductible officers' compensation	8,651	4,883	24,387
Acquisition costs	563	3,226	8,901
Other	(3,397)	1,964	344
Change in valuation allowance	116,562	130,156	150,277
Provision for income taxes	$ 271	$ 978	$ 618
U.S. Federal taxes (benefit) at statutory rate (as a percent)	21.00%	21.00%	21.00%
State tax expense (as a percent)	3.10%	3.96%	6.20%
Research and development credits (as a percent)	2.49%	1.28%	1.95%
Stock-based compensation (as a percent)	1.48%	(0.72%)	9.79%
Foreign tax differential (as a percent)	0.02%	(0.06%)	(0.04%)
Nondeductible officers' compensation (as a percent)	(1.99%)	(0.89%)	(5.18%)
Acquisition costs (as a percent)	(0.13%)	(0.59%)	(1.89%)
Other (as a percent)	0.79%	(0.36%)	(0.05%)
Change in valuation allowance (as a percent)	(26.82%)	(23.80%)	(31.90%)
Provision for income taxes (as a percent)	(0.06%)	(0.18%)	(0.13%)
Income tax expense	$ 271	$ 978	$ 618