Condensed Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Series A Preferred Convertible Stock Preferred Stock [Member]	Common stock	Additional paid-in capital	Accumulated deficit	Total
Balance at Dec. 31, 2019			$ 927	$ (36,557)	$ (35,630)
Balance (shares) at Dec. 31, 2019		1,099,270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense			185		185
Exercise of common stock warrants			3		3
Exercise of common stock warrants (shares)		13,123
Net loss				(5,387)	(5,387)
Balance at Jun. 30, 2020			1,115	(41,944)	(40,829)
Balance (shares) at Jun. 30, 2020		1,112,393
Balance at Dec. 31, 2019	$ 38,894
Balance (shares) at Dec. 31, 2019	4,443,259
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series A convertible preferred stock	$ 9,497
Sale of Series A convertible preferred stock (shares)	1,226,925
Balance at Jun. 30, 2020	$ 48,391
Balance (shares) at Jun. 30, 2020	5,670,184
Balance at Mar. 31, 2020			1,073	(39,234)	(38,161)
Balance (shares) at Mar. 31, 2020		1,099,270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense			39		39
Exercise of stock options			3		3
Exercise of stock options (shares)		13,123
Net loss				(2,710)	(2,710)
Balance at Jun. 30, 2020			1,115	(41,944)	(40,829)
Balance (shares) at Jun. 30, 2020		1,112,393
Balance at Mar. 31, 2020	$ 38,939
Balance (shares) at Mar. 31, 2020	4,447,981
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series A convertible preferred stock	$ 9,452
Sale of Series A convertible preferred stock (shares)	1,222,203
Balance at Jun. 30, 2020	$ 48,391
Balance (shares) at Jun. 30, 2020	5,670,184
Balance at Dec. 31, 2020		$ 1	95,738	(54,394)	41,345
Balance (shares) at Dec. 31, 2020		10,634,245
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock and common stock warrants, net of $596 in offering costs			26,404		26,404
Sale of common stock and common stock warrants, shares		1,000,000
Share-based compensation expense			1,074		1,074
Exercise of common stock warrants			906		906
Exercise of common stock warrants (shares)		146,017
Exercise of stock options			27		27
Exercise of stock options (shares)		32,530
Net loss				(9,139)	(9,139)
Balance at Jun. 30, 2021		$ 1	124,149	(63,533)	60,617
Balance (shares) at Jun. 30, 2021		11,812,792
Balance at Mar. 31, 2021		$ 1	96,174	(58,292)	37,883
Balance (shares) at Mar. 31, 2021		10,660,181
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock and common stock warrants, net of $596 in offering costs			26,404		26,404
Sale of common stock and common stock warrants, shares		1,000,000
Share-based compensation expense			749		749
Exercise of common stock warrants			801		801
Exercise of common stock warrants (shares)		134,351
Exercise of stock options			21		21
Exercise of stock options (shares)		18,260
Net loss				(5,241)	(5,241)
Balance at Jun. 30, 2021		$ 1	$ 124,149	$ (63,533)	$ 60,617
Balance (shares) at Jun. 30, 2021		11,812,792