Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 14, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares Under Option
Beginning balance (in shares)		3,811,229	6,177,126	5,814,581
Options granted (in shares)		0	0	4,559,820
Options exercised (in shares)		(342,350)	(116,681)	(210,806)
Options forfeited (in shares)		(417,379)	(2,249,216)	(3,986,469)
Ending balance (in shares)	3,600,000	3,051,500	3,811,229	6,177,126
Options exercisable ending balance (in shares)		1,930,911
Weighted- Average Exercise Price per Share
Beginning balance (in dollars per share)		$ 4.80	$ 8.87	$ 17.73
Options granted (in dollars per share)		0	0	11.29
Options exercised (in dollars per share)	$ 2.75	2.76	2.75	6.64
Options forfeited (in dollars per share)		11.09	16.09	15.07
Ending balance (in dollars per share)		4.17	$ 4.80	$ 8.87
Options exercisable ending balance (in dollars per share)		$ 4.99
Weighted- Average Remaining Contractual Life, Outstanding		7 years	7 years 10 months 24 days	8 years 2 months 12 days
Weighted- Average Remaining Contractual Life, Exercisable		7 years
Aggregate Intrinsic Value, Outstanding		$ 5.3	$ 5.6	$ 8.0
Aggregate Intrinsic Value, Exercisable		$ 3.0