Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - Employee And Non Employee - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 54,528	$ 21,825	$ 8,981
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	28,302	11,195	4,152
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 26,226	$ 10,630	$ 4,829