Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($)		Total	Preferred Stock	Preferred Stock	Preferred Stock Preferred Stock	Common Stock		Additional Paid-in Capital	Additional Paid-in Capital Preferred Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at the beginning of the period (in shares) at Dec. 31, 2019				0		2,486,000	[1]
Balance at the beginning of the period at Dec. 31, 2019		$ 3,996,000		$ 0		$ 0		$ 128,873,000		$ (3,000)	$ (124,874,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock option and stock purchase plans (in shares)	[1]					5,000
Issuance of common stock under employee stock option and stock purchase plans		0
Issuance of common stock and warrants (in shares)	[1]					688,000
Issuance of common stock and warrants		2,749,000						2,749,000
Offering costs on issuance of common stock and warrants		(474,000)						(474,000)
Warrant liability		(1,636,000)						(1,636,000)
Conversion of notes to preferred stock (in shares)					2,709,000
Conversion of notes to preferred stock			$ 1,769,000						$ 1,769,000
Stock-based compensation		20,000						20,000
Net loss from continuing operations		(541,000)									(541,000)
Balance at the end of the period (in shares) at Mar. 31, 2020				2,709,000		3,179,000	[1]
Balance at the end of the period at Mar. 31, 2020		5,883,000		$ 0		$ 0		131,301,000		(3,000)	(125,415,000)
Balance at the beginning of the period (in shares) at Dec. 31, 2020				2,597,000		3,525,000	[1]
Balance at the beginning of the period 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)	[1]					1,000
Issuance of common stock under employee stock option and stock purchase plans		$ 0
Issuance of common stock upon the exercise of warrants (in shares)		156,446				156,000	[1]
Issuance of common stock upon the exercise of warrants		$ 527,000						527,000
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units (in shares)	[1]					0
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units		(2,000)						(2,000)
Stock-based compensation		140,000						140,000
Net loss from continuing operations		(1,642,000)									(1,642,000)
Balance at the end of the period (in shares) at Mar. 31, 2021				2,597,000		3,682,000	[1]
Balance at the end of the period at Mar. 31, 2021		$ 3,278,000		$ 0		$ 0		$ 135,778,000		$ (3,000)	$ (132,497,000)

[1] *Shares outstanding for prior periods have been restated for the 1-for-5 reverse stock split effective June 11, 2020.