Statements of changes in convertible preferred stock and stockholders' equity (deficit) - USD ($) $ in Thousands	Series A Preferred Stock	Common stock	Additional paid-in capital	Accumulated deficit	Total
Balance at Dec. 31, 2018			$ 908	$ (26,113)	$ (25,205)
Balance (shares) at Dec. 31, 2018		1,087,821
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense			14		14
Exercise of stock options			5		5
Exercise of stock options (shares)		11,449
Net loss				(10,444)	(10,444)
Balance at Dec. 31, 2019			927	(36,557)	(35,630)
Balance (shares) at Dec. 31, 2019		1,099,270
Balance at Dec. 31, 2018	$ 27,513
Balance (shares) at Dec. 31, 2018	3,108,776
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series A convertible preferred stock upon conversion of debt	$ 6,800
Issuance of Series A convertible preferred stock upon conversion of debt (shares)	821,657
Sale of Series A convertible preferred stock and warrants with a fair value of $1,522, net of $35 and $49 of issuance costs	$ 4,581
Sale of Series A convertible preferred stock and warrants with a fair value of $1,522, net of $35 and $49 of issuance costs (shares)	512,826
Balance at Dec. 31, 2019	$ 38,894				38,894
Balance (shares) at Dec. 31, 2019	4,443,259
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Series A convertible preferred stock upon IPO		$ 1	48,368		48,369
Conversion of Series A convertible preferred stock upon IPO (in shares)		5,670,184
Conversion of liability-classified warrants upon IPO			7,060		7,060
Sale of common stock in connection with IPO, net of $6,108 of issuance costs			38,742		38,742
Sale of common stock in connection with IPO, net of $6,108 of issuance costs (in shares)		3,737,500
Share-based compensation expense			621		621
Exercise of stock options			20		20
Exercise of stock options (shares)		127,291
Net loss				(17,837)	(17,837)
Balance at Dec. 31, 2020		$ 1	$ 95,738	$ (54,394)	$ 41,345
Balance (shares) at Dec. 31, 2020		10,634,245
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series A convertible preferred stock and warrants with a fair value of $1,522, net of $35 and $49 of issuance costs	$ 9,475
Sale of Series A convertible preferred stock and warrants with a fair value of $1,522, net of $35 and $49 of issuance costs (shares)	1,226,925
Conversion of Series A convertible preferred stock upon IPO	$ (48,369)
Conversion of Series A convertible preferred stock upon IPO (in shares)	(5,670,184)
Balance (shares) at Dec. 31, 2020	0