Capital Structure - Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Number of Options
Options outstanding at the beginning of the period (in shares)	4,715
Options Granted (in shares)	2
Options Exercised (in shares)	0
Options Cancelled (in shares)	(234)
Options outstanding at the end of the period (in shares)	4,483
Vested and exercisable (in shares)	1,776
Weighted-Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 6.53
Options Granted (in dollars per share)	2.06
Options Exercised (in dollars per share)	0
Options Cancelled (in dollars per share)	8.93
Balance at the end of the period (in dollars per share)	6.37
Vested and exercisable (in dollars per share)	$ 10.71
Weighted-Average Remaining Contractual Term (Years)
Outstanding	4 years 9 months 18 days
Vested and exercisable	3 years 5 months 4 days
Aggregate Intrinsic Value
Outstanding	$ 0
Vested and exercisable	0
Additional disclosures related to stock options
Total intrinsic value for stock options exercisable	0	$ 0
Total intrinsic value for stock options exercised	$ 0	$ 0