Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	September 2020 At The Market Offering [Member] Common Stock [Member]	September 2020 At The Market Offering [Member] Additional Paid-in Capital [Member]	September 2020 At The Market Offering [Member] Retained Earnings [Member]	September 2020 At The Market Offering [Member] Treasury Stock [Member]	September 2020 At The Market Offering [Member]	Share Purchase Agreement, December 2019 [Member] Common Stock [Member]	Share Purchase Agreement, December 2019 [Member] Additional Paid-in Capital [Member]	Share Purchase Agreement, December 2019 [Member] Retained Earnings [Member]	Share Purchase Agreement, December 2019 [Member] Treasury Stock [Member]	Share Purchase Agreement, December 2019 [Member]	March 2021 Public Offering [Member] Common Stock [Member]	March 2021 Public Offering [Member] Additional Paid-in Capital [Member]	March 2021 Public Offering [Member] Retained Earnings [Member]	March 2021 Public Offering [Member] Treasury Stock [Member]	March 2021 Public Offering [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2019																13,697,000
Balance at Dec. 31, 2019																$ 14	$ 763,097	$ (685,122)	$ (3,054)	$ 74,935
Net loss																		(6,534)		(6,534)
Stock-based compensation expense																	1,689			1,689
Balance (in shares) at Mar. 31, 2020																13,697,000
Balance at Mar. 31, 2020																$ 14	764,786	(691,656)	$ (3,054)	70,090
Balance (in shares) at Dec. 31, 2020																16,922,000
Balance at Dec. 31, 2020																$ 17	790,277	(717,688)	$ (3,054)	69,552
Net loss																		(8,961)		(8,961)
Stock-based compensation expense																	2,443			2,443
Issuance of common stock, ATM Program (in shares)	105,000				105,083
Issuance of common stock, ATM Program		$ 570			$ 570
Issuance of common stock warrants, equity consideration for service agreement							$ 494			$ 494
Issuance of common stock and common stock warrants, net of issuance costs (in shares)											9,230,000
Issuance of common stock and common stock warrants, net of issuance costs											$ 9	$ 27,381			$ 27,390
Balance (in shares) at Mar. 31, 2021																26,257,000
Balance at Mar. 31, 2021																$ 26	$ 821,165	$ (726,649)	$ (3,054)	$ 91,488