Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Balances at Dec. 31, 2019	$ 99,000	$ 172,015,000	$ (157,521,000)	$ 14,593,000
Balances (in shares) at Dec. 31, 2019	9,922,758
Forfeiture of restricted stock awards (in shares)	(4,010)
Sale of common stock, net of issuance costs	$ 87,000	22,723,000		22,810,000
Sale of common stock, net of issuance costs (in shares)	8,710,800
Exercise of warrants		81,000		81,000
Exercise of warrants (in shares)	14,464
Return of restricted stock awards for tax withholdings		(8,000)		(8,000)
Return of restricted stock awards for tax withholdings, shares	(2,511)
Exercise stock options	$ 1,000	86,000		87,000
Exercise of stock options (in shares)	27,382
Stock-based compensation		2,613,000		2,613,000
Net loss			(15,557,000)	(15,557,000)
Balances at Sep. 30, 2020	$ 187,000	197,510,000	(173,078,000)	24,619,000
Balances (in shares) at Sep. 30, 2020	18,668,883
Balances at Jun. 30, 2020	$ 186,000	196,761,000	(167,309,000)	29,638,000
Balances (in shares) at Jun. 30, 2020	18,641,501
Exercise stock options	$ 1,000	86,000		87,000
Exercise of stock options (in shares)	27,382
Stock-based compensation		663,000		663,000
Net loss			(5,769,000)	(5,769,000)
Balances at Sep. 30, 2020	$ 187,000	197,510,000	(173,078,000)	24,619,000
Balances (in shares) at Sep. 30, 2020	18,668,883
Balances at Dec. 31, 2020	$ 187,000	198,372,000	(179,702,000)	18,857,000
Balances (in shares) at Dec. 31, 2020	18,688,461
Forfeiture of restricted stock awards (in shares)	(1,047)
Sale of common stock, net of issuance costs	$ 61,000	19,302,000		19,363,000
Sale of common stock, net of issuance costs (in shares)	6,153,847
Exercise of warrants	$ 1,000	290,000		291,000
Exercise of warrants (in shares)	52,000
Return of restricted stock awards for tax withholdings		(106,000)		(106,000)
Return of restricted stock awards for tax withholdings, shares	(25,424)
Exercise stock options		240,000		$ 240,000
Exercise of stock options (in shares)	73,517			73,517
Issuance of inducement stock awards (in shares)	23,732
Stock-based compensation		2,218,000		$ 2,218,000
Net loss			(17,108,000)	(17,108,000)
Balances at Sep. 30, 2021	$ 249,000	220,316,000	(196,810,000)	23,755,000
Balances (in shares) at Sep. 30, 2021	24,965,086
Balances at Jun. 30, 2021	$ 249,000	219,761,000	(191,391,000)	28,619,000
Balances (in shares) at Jun. 30, 2021	24,937,826
Forfeiture of restricted stock awards (in shares)	(123)
Exercise stock options		86,000		86,000
Exercise of stock options (in shares)	27,383
Stock-based compensation		469,000		469,000
Net loss			(5,419,000)	(5,419,000)
Balances at Sep. 30, 2021	$ 249,000	$ 220,316,000	$ (196,810,000)	$ 23,755,000
Balances (in shares) at Sep. 30, 2021	24,965,086