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]
Stock-based compensation expense	$ 2,536	$ 249	$ 2,966	$ 689
Research and Development
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	374	103	486	278
General and Administrative
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,162	$ 146	$ 2,480	$ 411