Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Number of Options
Outstanding at beginning of period (in shares)	4,146	3,259
Granted (in shares)	2,015	1,212
Forfeited and Expired (in shares)	(133)	(264)
Exercised (in shares)	0	(61)
Outstanding at end of period (in shares)	6,028	4,146	3,259
Vested or expected to vest (in shares)	5,877
Exercisable at end of period (in shares)	3,652
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 7.28	$ 8.14
Granted (in dollars per share)	1.83	4.73
Forfeited and Expired (in dollars per share)	7.81	7.52
Exercised (in dollars per share)	0
Outstanding at end of period (in dollars per share)	5.48	$ 7.28	$ 8.14
Vested or expected to vest at end of period (in dollars per share)	5.57
Exercisable at end of period (in dollars per share)	$ 7.42
Weighted Average Remaining Contractual Term in Years
Weighted average remaining contractual term	7 years 6 months	7 years 10 months 17 days	8 years 5 months 1 day
Weighted average remaining contractual term, vested or expected to vest	7 years 5 months 15 days
Weighted average remaining contractual term, exercisable	6 years 6 months 25 days
Aggregate Intrinsic Value
Intrinsic value	$ 38	$ 1,423	$ 2,978
Intrinsic value, vested or expected to vest at end of period	36
Intrinsic value, exercisable at end of period	$ 0