Stock-Based Compensation - Summary of Activity Under Stock Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance (in shares)	4,173,168	4,564,735
Granted (in shares)	600,000	100,000
Stock option exercised (in shares)	(253,335)	0
Expired (in shares)	(2,035,966)	(486,666)
Forfeited (in shares)	(29,167)	(4,901)
Outstanding, Ending Balance (in shares)	2,454,700	4,173,168	4,564,735
Vested and exercisable as of December 31, 2021 (in shares)	1,848,033
Weighted Average Exercise Price
Outstanding Weighted Average Exercise Price, Beginning Balance	$ 6.83	$ 8.54
Weighted Average Exercise Price, Granted	3.22	3.45
Weighted Average Exercise Price, Exercised	1.31		$ 1.31
Weighted Average Exercise Price, Expired	9.14	13.82
Weighted Average Exercise Price, Forfeited	5.89	6.57
Outstanding Weighted Average Exercise Price, Ending Balance	4.62	$ 6.83	$ 8.54
Weighted Average Exercise Price, Vested and exercisable as of end of period	$ 5.06
Weighted -Average Remaining contractual Term (in years)
Weighted Average Remaining Contractual Term (in years), Outstanding as Beginning of period	4 years 6 months 29 days	3 years 6 months 29 days	5 years 1 month 2 days
Weighted Average Remaining Contractual Term (in years), Outstanding as of end of period	4 years 6 months 29 days	3 years 6 months 29 days	5 years 1 month 2 days
Weighted Average Remaining Contractual Term (in years), Vested and exercisable as of end of period	3 years 2 months 1 day
Additional disclosures
Aggregate Intrinsic Value, Outstanding as of beginning of period	$ 1,324	$ 4,513
Aggregate Intrinsic Value, Outstanding as of end of period	109	$ 1,324	$ 4,513
Aggregate Intrinsic Value, Vested and exercisable as of end of period	$ 109