Correction of Prior Period Errors - Statement of Comprehensive Loss Year Ended (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss	$ (2,663)	$ (29,738)	$ (16,751)	$ (3,814)	$ (22,218)	$ 3,011	$ (22,361)	$ (12,585)	$ (20,565)	$ (50,303)	$ (52,966)	$ (54,153)	$ (30,240)
Comprehensive loss		(30,071)								(60,407)	$ (53,573)	(56,376)	$ (46,308)
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss		(22,381)	(16,751)	(3,814)					(20,565)	(42,946)		(61,510)
Comprehensive loss		(22,714)								(53,050)		(63,733)
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss		(7,357)	$ 0	$ 0					$ 0	(7,357)		7,357
Comprehensive loss		$ (7,357)								$ (7,357)		$ 7,357