Stock-Based Compensation - Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee and non-employee stock options
Stock based compensation expense
Options granted (in shares)	391,000
Stock-based compensation expense	$ 115,219	$ 50,171	$ 28,624
Unrecognized compensation expense	$ 233,300
Unrecognized compensation expense, weighted average period of recognition	2 years 10 months 24 days
Employee and non-employee stock options | Cost of revenues
Stock based compensation expense
Stock-based compensation expense	$ 4,811	1,691	937
Employee and non-employee stock options | Research and development
Stock based compensation expense
Stock-based compensation expense	25,868	11,424	5,354
Employee and non-employee stock options | Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	84,540	37,056	22,333
Employee stock options
Stock based compensation expense
Stock-based compensation expense	113,686	49,215	27,989
Employee stock options | Cost of revenues
Stock based compensation expense
Stock-based compensation expense	4,811	1,691	905
Employee stock options | Research and development
Stock based compensation expense
Stock-based compensation expense	24,507	10,777	5,354
Employee stock options | Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	$ 84,368	36,747	21,730
Non-employee stock options
Stock based compensation expense
Options granted (in shares)	31,553
Options unvested (in shares)	730
Stock-based compensation expense	$ 1,533	956	635
Non-employee stock options | Cost of revenues
Stock based compensation expense
Stock-based compensation expense			32
Non-employee stock options | Research and development
Stock based compensation expense
Stock-based compensation expense	1,361	647
Non-employee stock options | Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	$ 172	$ 309	$ 603