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	$ 38,894		$ 927	$ (36,557)	$ (35,630)
Balance (shares) at Dec. 31, 2019	4,443,259	1,099,270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of Series A convertible preferred stock	$ 45
Sale of Series A convertible preferred stock (shares)	4,722
Share-based compensation expense			146		146
Net loss				(2,677)	(2,677)
Balance at Mar. 31, 2020	$ 38,939		1,073	(39,234)	(38,161)
Balance (shares) at Mar. 31, 2020	4,447,981	1,099,270
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]
Share-based compensation expense			325		325
Exercise of common stock warrants			105		105
Exercise of common stock warrants (shares)		11,666
Exercise of stock options			6		6
Exercise of stock options (shares)		14,270
Net loss				(3,898)	(3,898)
Balance at Mar. 31, 2021		$ 1	$ 96,174	$ (58,292)	$ 37,883
Balance (shares) at Mar. 31, 2021		10,660,181