Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred stock Convertible Preferred Stock	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2020		1,931,860	6,743,271
Beginning balance at Dec. 31, 2020	$ 26,026	$ 2	$ 7	$ 453,062	$ 0	$ (427,045)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)			2,768
Issuance of common stock upon exercise of options	26			26
Issuance of common stock upon exercise of warrants (in shares)			266,866
Issuance of common stock upon exercise of warrants	832			832
Issuance of common stock upon vesting of restricted stock units (in shares)			3,363
Issuance of common stock, preferred stock and warrants from private placement, net of offering costs (in shares)		3,725,720	5,892,335
Issuance of common stock, preferred stock and warrants from private placement, net of offering costs	32,359	$ 3	$ 6	32,350
Stock-based compensation expense	2,923			2,923
Issuance of common stock under Employee Stock Purchase Plan (in shares)			1,160
Issuance of common stock under Employee Stock Purchase Plan	7			7
Issuance of common stock through ATM (in shares)			1,601,734
Issuance of common stock through ATM	20,593		$ 2	20,591
Conversions of convertible preferred stock (in shares)		(85,621)	85,621
Conversions of convertible preferred stock	0
Unrealized loss on short-term investments, net	0
Net loss	(27,808)					(27,808)
Ending balance (in shares) at Dec. 31, 2021		5,571,959	14,597,118
Ending balance at Dec. 31, 2021	54,958	$ 5	$ 15	509,791	0	(454,853)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			36,300
Stock-based compensation expense	2,177			2,177
Issuance of common stock under Employee Stock Purchase Plan (in shares)			1,743
Issuance of common stock under Employee Stock Purchase Plan	3			3
Issuance of common stock through ATM (in shares)			2,205,100
Issuance of common stock through ATM	4,488		$ 2	4,486
Unrealized loss on short-term investments, net	(12)				(12)
Net loss	(28,323)					(28,323)
Ending balance (in shares) at Dec. 31, 2022		5,571,959	16,840,261
Ending balance at Dec. 31, 2022	$ 33,291	$ 5	$ 17	$ 516,457	$ (12)	$ (483,176)