Consolidated Statements of Stockholders' (Deficit) Equity - USD ($)	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	3,525,000
Beginning balance at Dec. 31, 2020	$ 4,255,000	$ 0	$ 0	$ 135,113,000	$ (3,000)	$ (130,855,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			79,000
Issuance of common stock under employee stock option and stock purchase plans	80,000			80,000
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units	(1,000)			(1,000)
Issuance of common stock and warrants (in shares)			2,183,000
Issuance of common stock and warrants	9,500,000			9,500,000
Offering costs on issuance of common stock and warrants	$ (969,000)			(969,000)
Issuance of common stock upon the exercise of warrants (in shares)	237,892		237,000
Issuance of common stock upon the exercise of warrants	$ 801,000			801,000
Conversion of convertible securities (in shares)		1,721,000	344,000
Stock-based compensation	429,000			429,000
Net loss	(7,886,000)					(7,886,000)
Ending balance (in shares) at Dec. 31, 2021		876,000	6,368,000
Ending balance at Dec. 31, 2021	6,209,000	$ 0	$ 0	144,953,000	(3,000)	(138,741,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)			46,000
Issuance of common stock under employee stock option and stock purchase plans	6,000			6,000
Issuance of common stock and warrants (in shares)			1,313,000
Issuance of common stock and warrants	3,500,000		$ 1,000	3,499,000
Offering costs on issuance of common stock and warrants	(334,000)			(334,000)
Issuance of common stock upon the exercise of warrants (in shares)			1,465,000
Stock-based compensation	117,000			117,000
Sale of common stock (in shares)			657,000
Stock issued in exchange transactions	304,000			304,000
Net loss	(10,279,000)					(10,279,000)
Ending balance (in shares) at Dec. 31, 2022		876,000	9,849,000
Ending balance at Dec. 31, 2022	(477,000)	$ 0	$ 1,000	148,545,000	(3,000)	(149,020,000)
Beginning balance at Sep. 30, 2022	5,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(2,310,000)
Ending balance (in shares) at Dec. 31, 2022		876,000	9,849,000
Ending balance at Dec. 31, 2022	$ (477,000)	$ 0	$ 1,000	$ 148,545,000	$ (3,000)	$ (149,020,000)