Stock-Based Payments - Summary of Stock-based Compensation Expense for Stock Options and Restricted Stock Units (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based Arrangement expense recognized	$ 2,096	$ 2,723	$ 7,479	$ 7,909
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based Arrangement expense recognized	1,485	1,229	4,260	3,459
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based Arrangement expense recognized	$ 611	$ 1,494	$ 3,219	$ 4,450