Common Stock and Preferred Stock - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (7,883)	$ (5,673)	$ (17,093)	$ (19,481)
Dividends on preferred stock - declared and undeclared	(2,239)	(464)	(6,716)	(464)
Net loss attributable to common stockholders	(10,122)	(6,137)	(23,809)	(19,945)
Net loss attributable to common stockholders	$ (10,122)	$ (6,137)	$ (23,809)	$ (19,945)
Weighted-average common shares outstanding, basic (in shares)	18,915	17,280	18,236	16,990
Weighted-average common shares outstanding, diluted (in shares)	18,915	17,280	18,236	16,990
Net loss per common share, basic (in dollars per share)	$ (0.54)	$ (0.36)	$ (1.31)	$ (1.17)
Net loss per common share, diluted (in dollars per share)	$ (0.54)	$ (0.36)	$ (1.31)	$ (1.17)