Reverse Recapitalization - Schedule of Proceeds from Reverse Capitalization (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 20, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Cash balance	$ 429,952	$ 125,403
Less redemption of Accel shares prior to reverse recapitalization	(413,733)	0	$ 0	$ (3,343)
Cash balance prior to backstop equity financing	16,219
Plus funds from Investment Private Placement	48,038
Cash balance	64,257	134,451	125,403
Payment for sponsor loan	(4,000)
Less impact from issuance of contingent earnout shares	(51,641)
Transaction costs related to the reverse recapitalization, net of tax	(31,005)
Net equity deficit prior to stock issuance	(22,389)		(22,379)
Impact of stock issued in reverse recapitalization	10	90,422	0	0
Net equity deficit from reverse recapitalization	(22,379)
Less impact from conversion of treasury stock and issuance of warrants	(7,414)	$ (19,924)	$ 0	$ 0
Net impact to additional paid-in-capital from reverse recapitalization	$ (29,793)