Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Placement Agents' Designees [Member] Common Stock [Member]	Placement Agents' Designees [Member] Additional Paid-in Capital [Member]	Placement Agents' Designees [Member] Retained Earnings [Member]	Placement Agents' Designees [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2019					48,254,994
Balances at Dec. 31, 2019					$ 5	$ 129,608	$ (116,661)		$ 12,952
Issuance of common stock (in shares)					4,000,000
Issuance of common stock					$ 0	8,722	0		8,722
Issuance of common stock upon exercise of common stock warrants (in shares)					43,707,286
Issuance of common stock upon exercise of common stock warrants					$ 5	24,653	0		$ 24,658
Issuance of common stock upon exercise of stock options (in shares)					178,381				178,381
Issuance of common stock upon exercise of stock options					$ 0	116	0		$ 116
Stock-based compensation					0	2,956	0		2,956
Net loss					0	0	(10,274)		(10,274)
Disgorgement of short-swing profits, net of costs					$ 0	652	0		652
Issuance of common stock warrants to placement agents’ designees	$ 0	$ 453	$ 0	$ 453
Balances (in shares) at Jun. 30, 2020					96,140,661
Balances at Jun. 30, 2020					$ 10	167,160	(126,935)		40,235
Balances (in shares) at Mar. 31, 2020					72,004,720
Balances at Mar. 31, 2020					$ 7	149,244	(117,958)		31,293
Issuance of common stock upon exercise of common stock warrants (in shares)					23,981,166
Issuance of common stock upon exercise of common stock warrants					$ 3	14,306	0		14,309
Issuance of common stock upon exercise of stock options (in shares)					154,775
Issuance of common stock upon exercise of stock options					$ 0	98	0		98
Stock-based compensation					0	2,860	0		2,860
Net loss					0	0	(8,977)		(8,977)
Disgorgement of short-swing profits, net of costs					$ 0	652	0		652
Balances (in shares) at Jun. 30, 2020					96,140,661
Balances at Jun. 30, 2020					$ 10	167,160	(126,935)		40,235
Balances (in shares) at Dec. 31, 2020					110,271,093
Balances at Dec. 31, 2020					$ 11	272,274	(148,881)	$ 0	123,404
Issuance of common stock (in shares)					10,958,908
Issuance of common stock					$ 1	101,913	0	0	101,914
Issuance of common stock upon exercise of common stock warrants (in shares)					1,012,540
Issuance of common stock upon exercise of common stock warrants					$ 0	1,849	0	0	$ 1,849
Issuance of common stock upon exercise of stock options (in shares)					571,926				571,926
Issuance of common stock upon exercise of stock options					$ 0	892	0	0	$ 892
Stock-based compensation					0	3,855	0	0	3,855
Unrealized loss on available-for-sale investments					0	0	0	(9)	(9)
Net loss					$ 0	0	(32,123)	0	(32,123)
Balances (in shares) at Jun. 30, 2021					122,814,467
Balances at Jun. 30, 2021					$ 12	380,783	(181,004)	(9)	199,782
Balances (in shares) at Mar. 31, 2021					117,963,912
Balances at Mar. 31, 2021					$ 12	341,116	(164,888)	(5)	176,235
Issuance of common stock (in shares)					4,304,541
Issuance of common stock					$ 0	36,202	0	0	36,202
Issuance of common stock upon exercise of common stock warrants (in shares)					181,818
Issuance of common stock upon exercise of common stock warrants					$ 0	200	0	0	200
Issuance of common stock upon exercise of stock options (in shares)					364,196
Issuance of common stock upon exercise of stock options					$ 0	661	0	0	661
Stock-based compensation					0	2,604	0	0	2,604
Unrealized loss on available-for-sale investments					0	0	0	(4)	(4)
Net loss					$ 0	0	(16,116)	0	(16,116)
Balances (in shares) at Jun. 30, 2021					122,814,467
Balances at Jun. 30, 2021					$ 12	$ 380,783	$ (181,004)	$ (9)	$ 199,782