CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		0	440,529
Beginning balance at Dec. 31, 2018	$ 5,245	$ 0	$ 1	$ 87,099	$ (81,855)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)			527,344
Issuance of common stock and common stock warrants, net of issuance costs	13,416			13,416
Issuance of common stock for exercise of warrants, net of offering costs (in shares)			63,000
Issuance of common stock for exercise of warrants, net of offering costs	3,275			3,275
Issuance of common stock upon exercise of pre-funded warrants (in shares)			971,830
Issuance of common stock upon exercise of pre-funded warrants	5		$ 1	4
Stock-based compensation	311			311
Impact of anti-dilution protection on liability-classified warrants	(243)			(243)
Net loss	(7,671)				(7,671)
Ending balance (in shares) at Jun. 30, 2019		0	2,002,703
Ending balance at Jun. 30, 2019	14,338	$ 0	$ 2	103,862	(89,526)
Beginning balance (in shares) at Mar. 31, 2019		0	483,529
Beginning balance at Mar. 31, 2019	2,950	$ 0	$ 1	89,341	(86,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)			527,344
Issuance of common stock and common stock warrants, net of issuance costs	13,416			13,416
Issuance of common stock for exercise of warrants, net of offering costs (in shares)			20,000
Issuance of common stock for exercise of warrants, net of offering costs	1,045			1,045
Issuance of common stock upon exercise of pre-funded warrants (in shares)			971,830
Issuance of common stock upon exercise of pre-funded warrants	5		$ 1	4
Stock-based compensation	126			126
Impact of anti-dilution protection on liability-classified warrants	(70)			(70)
Net loss	(3,134)				(3,134)
Ending balance (in shares) at Jun. 30, 2019		0	2,002,703
Ending balance at Jun. 30, 2019	14,338	$ 0	$ 2	103,862	(89,526)
Beginning balance (in shares) at Dec. 31, 2019		0	5,080,100
Beginning balance at Dec. 31, 2019	6,093	$ 0	$ 5	107,235	(101,147)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)			1,189,000
Issuance of common stock and common stock warrants, net of issuance costs	5,963		$ 1	5,962
Issuance of common stock upon exercise of pre-funded warrants (in shares)			448,800
Issuance of common stock upon exercise of pre-funded warrants	4		$ 1	3
Stock-based compensation	291			291
Net loss	(8,568)				(8,568)
Ending balance (in shares) at Jun. 30, 2020		0	6,717,900
Ending balance at Jun. 30, 2020	3,783	$ 0	$ 7	113,491	(109,715)
Beginning balance (in shares) at Mar. 31, 2020		0	6,717,900
Beginning balance at Mar. 31, 2020	8,062	$ 0	$ 7	113,345	(105,290)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	146			146
Net loss	(4,425)				(4,425)
Ending balance (in shares) at Jun. 30, 2020		0	6,717,900
Ending balance at Jun. 30, 2020	$ 3,783	$ 0	$ 7	$ 113,491	$ (109,715)