Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		2,597,000
Beginning balance at Dec. 31, 2020	$ 4,255	$ 0	$ 0	$ 135,113	$ (3)	$ (130,855)
Beginning balance (in shares) at Dec. 31, 2020			3,525,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			1,000
Issuance of common stock upon the exercise of warrants (in shares)			156,000
Issuance of common stock upon the exercise of warrants	527			527
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units	(2)			(2)
Stock-based compensation	140			140
Net loss	(1,642)					(1,642)
Ending balance (in shares) at Mar. 31, 2021			3,682,000
Ending balance (in shares) at Mar. 31, 2021		2,597,000
Ending balance at Mar. 31, 2021	3,278	$ 0	$ 0	135,778	(3)	(132,497)
Beginning balance (in shares) at Dec. 31, 2020		2,597,000
Beginning balance at Dec. 31, 2020	4,255	$ 0	$ 0	135,113	(3)	(130,855)
Beginning balance (in shares) at Dec. 31, 2020			3,525,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,255)
Ending balance (in shares) at Sep. 30, 2021			5,087,000
Ending balance (in shares) at Sep. 30, 2021		876,000
Ending balance at Sep. 30, 2021	4,502	$ 0	$ 0	140,615	(3)	(136,110)
Beginning balance (in shares) at Mar. 31, 2021		2,597,000
Beginning balance at Mar. 31, 2021	3,278	$ 0	$ 0	135,778	(3)	(132,497)
Beginning balance (in shares) at Mar. 31, 2021			3,682,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			69,000
Issuance of common stock under employee stock option and stock purchase plans	59			59
Issuance of common stock (in shares)			990,000
Issuance of common stock	5,000			5,000
Offering costs on issuance of common stock and warrants	(469)			(469)
Issuance of common stock upon conversion from preferred stock (in shares)		(1,721,000)	344,000
Stock-based compensation	208			208
Net loss	(2,473)					(2,473)
Ending balance (in shares) at Jun. 30, 2021			5,085,000
Ending balance (in shares) at Jun. 30, 2021		876,000
Ending balance at Jun. 30, 2021	5,603	$ 0	$ 0	140,576	(3)	(134,970)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			2,000
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units	1			1
Offering costs on issuance of common stock and warrants	(1)			(1)
Stock-based compensation	39			39
Net loss	(1,140)					(1,140)
Ending balance (in shares) at Sep. 30, 2021			5,087,000
Ending balance (in shares) at Sep. 30, 2021		876,000
Ending balance at Sep. 30, 2021	4,502	$ 0	$ 0	140,615	(3)	(136,110)
Beginning balance (in shares) at Dec. 31, 2021		876,000
Beginning balance at Dec. 31, 2021	$ 6,209	$ 0	$ 0	144,953	(3)	(138,741)
Beginning balance (in shares) at Dec. 31, 2021	6,368,549		6,368,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of warrants (in shares)			85,000
Stock-based compensation	$ 44			44
Net loss	(2,821)					(2,821)
Ending balance (in shares) at Mar. 31, 2022			6,453,000
Ending balance (in shares) at Mar. 31, 2022		876,000
Ending balance at Mar. 31, 2022	3,432	$ 0	$ 0	144,997	(3)	(141,562)
Beginning balance (in shares) at Dec. 31, 2021		876,000
Beginning balance at Dec. 31, 2021	$ 6,209	$ 0	$ 0	144,953	(3)	(138,741)
Beginning balance (in shares) at Dec. 31, 2021	6,368,549		6,368,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (7,969)
Ending balance (in shares) at Sep. 30, 2022	9,191,108		9,191,000
Ending balance (in shares) at Sep. 30, 2022		876,000
Ending balance at Sep. 30, 2022	$ 1,526	$ 0	$ 1	148,238	(3)	(146,710)
Beginning balance (in shares) at Mar. 31, 2022		876,000
Beginning balance at Mar. 31, 2022	3,432	$ 0	$ 0	144,997	(3)	(141,562)
Beginning balance (in shares) at Mar. 31, 2022			6,453,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			45,000
Issuance of common stock under employee stock option and stock purchase plans	5			5
Issuance of common stock upon the exercise of warrants (in shares)			1,313,000
Issuance of common stock upon the exercise of warrants	3,500		$ 1	3,499
Offering costs on issuance of common stock and warrants	(334)			(334)
Stock-based compensation	54			54
Net loss	(2,486)					(2,486)
Ending balance (in shares) at Jun. 30, 2022			7,811,000
Ending balance (in shares) at Jun. 30, 2022		876,000
Ending balance at Jun. 30, 2022	4,171	$ 0	$ 1	148,221	(3)	(144,048)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			1,000
Issuance of common stock upon the exercise of warrants (in shares)			1,379,000
Stock-based compensation	17			17
Net loss	$ (2,662)					(2,662)
Ending balance (in shares) at Sep. 30, 2022	9,191,108		9,191,000
Ending balance (in shares) at Sep. 30, 2022		876,000
Ending balance at Sep. 30, 2022	$ 1,526	$ 0	$ 1	$ 148,238	$ (3)	$ (146,710)