Common Stock and Stockholders' Equity - Schedule of Compensation Expense (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 15, 2018	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	$ 400	$ 2,288	$ 5,440
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		309	2,256
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		$ 1,979	$ 3,184