Condensed Consolidated Statements of Changes in Stockholders' Deficit - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2019	$ 34	$ 124,318	$ (130,474)	$ (6,122)
Balance (in shares) at Dec. 31, 2019	33,562,885
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	$ 0	1,860	0	1,860
Share-based compensation expense (in shares)	0
Vested restricted stock units	$ 0	(37)	0	(37)
Vested restricted stock units (in shares)	19,811
Net loss	$ 0	0	(16,530)	(16,530)
Balance at Mar. 31, 2020	$ 34	126,141	(147,004)	(20,829)
Balance (in shares) at Mar. 31, 2020	33,582,696
Balance at Dec. 31, 2020	$ 35	137,725	(186,257)	(48,497)
Balance (in shares) at Dec. 31, 2020	34,569,254
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under public equity offering	$ 1	10,196	0	10,197
Common stock issued under public equity offering (in shares)	1,672,104
Costs of common stock issuance under public equity offering	$ 0	(306)	0	(306)
Costs of common stock issuance under public equity offering (in shares)	0
Share-based compensation expense	$ 0	1,507	0	1,507
Share-based compensation expense (in shares)	0
Other	$ 0	(27)	0	(27)
Net loss	0	0	(14,672)	(14,672)
Balance at Mar. 31, 2021	$ 36	$ 149,095	$ (200,929)	$ (51,798)
Balance (in shares) at Mar. 31, 2021	36,241,358