Stock-Based Compensation - Schedule of Stock-based Compensation Expense Recorded in Operating Expenses (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 in operating expenses	$ 886	$ 6,857	$ 2,793	$ 20,726
Selling, General and Administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation in operating expenses	771	6,603	2,476	19,286
Research and Development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation in operating expenses	$ 115	$ 254	$ 317	$ 1,440