STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2018	$ 6,032	$ 1	$ 144,965	$ (138,934)
Beginning Balance, shares at Dec. 31, 2018		773,558
Issuance of common stock for cash, net of offering costs	2,900		2,900
Issuance of common stock for cash, net of offering costs, shares		325,304
Share-based compensation	50		50
Adjustment for fractional shares		(49)
Net loss	(1,664)			(1,664)
Ending Balance at Mar. 31, 2019	7,318	$ 1	147,915	(140,598)
Ending Balance, shares at Mar. 31, 2019		1,098,813
Beginning Balance at Dec. 31, 2018	6,032	$ 1	144,965	(138,934)
Beginning Balance, shares at Dec. 31, 2018		773,558
Net loss	(4,256)
Ending Balance at Sep. 30, 2019	8,799	$ 2	151,987	(143,190)
Ending Balance, shares at Sep. 30, 2019		1,594,070
Beginning Balance at Mar. 31, 2019	7,318	$ 1	147,915	(140,598)
Beginning Balance, shares at Mar. 31, 2019		1,098,813
Issuance of common stock for cash, net of offering costs	3,262		3,262
Issuance of common stock for cash, net of offering costs, shares		356,743
Share-based compensation	45		45
Net loss	(1,436)			(1,436)
Ending Balance at Jun. 30, 2019	9,189	$ 1	151,222	(142,034)
Ending Balance, shares at Jun. 30, 2019		1,455,556
Issuance of common stock for cash, net of offering costs	737	$ 1	736
Issuance of common stock for cash, net of offering costs, shares		138,514
Share-based compensation	29		29
Net loss	(1,156)			(1,156)
Ending Balance at Sep. 30, 2019	8,799	$ 2	151,987	(143,190)
Ending Balance, shares at Sep. 30, 2019		1,594,070
Share-based compensation	27		27
Other	10		10
Net loss	(1,226)			(1,226)
Ending Balance at Dec. 31, 2019	$ 7,610	$ 2	152,024	(144,416)
Ending Balance, shares at Dec. 31, 2019	1,594,070	1,594,070
Share-based compensation	$ 16		16
Net loss	(1,320)			(1,320)
Ending Balance at Mar. 31, 2020	6,306	$ 2	152,040	(145,736)
Ending Balance, shares at Mar. 31, 2020		1,594,070
Beginning Balance at Dec. 31, 2019	$ 7,610	$ 2	152,024	(144,416)
Beginning Balance, shares at Dec. 31, 2019	1,594,070	1,594,070
Net loss	$ (4,613)
Ending Balance at Sep. 30, 2020	$ 50,455	$ 9	199,475	(149,029)
Ending Balance, shares at Sep. 30, 2020	9,285,624	9,285,624
Beginning Balance at Mar. 31, 2020	$ 6,306	$ 2	152,040	(145,736)
Beginning Balance, shares at Mar. 31, 2020		1,594,070
Issuance of common stock and exercise of prefunded warrants for cash,net of offering costs	5,297		5,297
Issuance of common stock and exercise of prefunded warrants for cash,net of offering costs, shares		673,500
Share-based compensation	4		4
Net loss	(1,302)			(1,302)
Ending Balance at Jun. 30, 2020	10,305	$ 2	157,341	(147,038)
Ending Balance, shares at Jun. 30, 2020		2,267,570
Issuance of common stock for cash, net of offering costs	42,136	$ 7	42,129
Issuance of common stock for cash, net of offering costs, shares		7,018,054
Share-based compensation	5		5
Net loss	(1,991)			(1,991)
Ending Balance at Sep. 30, 2020	$ 50,455	$ 9	$ 199,475	$ (149,029)
Ending Balance, shares at Sep. 30, 2020	9,285,624	9,285,624