Income Taxes - Effective Tax Rates (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective tax rates differing from U.S. federal statutory rate
U.S. Federal taxes (benefit) at statutory rate	$ (98,931,000)	$ (48,226,000)	$ (25,794,000)
State tax expense	(29,206,000)	(10,672,000)	(6,607,000)
Research and development credits	(9,193,000)	(3,964,000)	(1,645,000)
Stock-based compensation	(46,128,000)	(23,791,000)	(7,544,000)
Foreign tax	167,000	55,000	1,612,000
Other nondeductible items	344,000	792,000	769,000
Nondeductible officers' compensation	24,387,000	8,984,000	609,000
Acquisition costs	8,901,000
Change in valuation allowance	150,277,000	76,920,000	40,599,000
Provision for income taxes	$ 618,000	$ 98,000	$ 1,999,000
U.S. Federal taxes (benefit) at statutory rate (as a percent)	(21.00%)	(21.00%)	(21.00%)
State tax expense (as a percent)	(6.20%)	(4.65%)	(5.38%)
Research and development credits (as a percent)	(1.95%)	(1.73%)	(1.34%)
Stock-based compensation (as a percent)	(9.80%)	(10.36%)	(6.14%)
Foreign tax differential (as a percent)	0.04%	0.02%	1.31%
Other nondeductible items (as a percent)	0.07%	0.35%	0.63%
Nondeductible officers' compensation (as a percent)	5.18%	3.91%	0.50%
Acquisition costs (as a percent)	1.89%
Change in valuation allowance (as a percent)	31.90%	33.50%	33.05%
Provision for income taxes (as a percent)	0.13%	0.04%	1.63%
Income tax expense	$ 618,000	$ 98,000	$ 1,999,000
Foreign withholding tax expense			1,900,000
Foreign income tax expense			100,000
State income tax expense	300,000	9,000	$ 40,000.00
Clinical testing and software licensing
Effective tax rates differing from U.S. federal statutory rate
Foreign income tax expense	$ 300,000	$ 100,000