Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,895	$ 676	$ 5,019	$ 1,737
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	1,026	312	2,794	867
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 869	$ 364	$ 2,225	$ 870