Net Loss Per Common Share - Basic Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (1,779)	$ (8,466)	$ (10,161)	$ (13,287)
Adjustments to reconcile to net (loss) income available to common stockholders
Accumulated dividend on Series B Convertible Preferred Stock	1,033	0	2,039	0
Accretion of increasing-rate dividend feature	464	0	926	0
Total adjustments	1,497	0	2,965	0
Net loss available to common stockholders	$ (3,276)	$ (8,466)	$ (13,126)	$ (13,287)
Weighted average common shares outstanding - basic (in shares)	110,276,636	108,119,461	109,841,428	108,081,625
Basic net loss per common share (in dollars per share)	$ (0.03)	$ (0.08)	$ (0.12)	$ (0.12)