CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($)	Total	Series F Preferred Stock	Preferred Stock Series F Preferred Stock	Common Stock	Common Stock Pre-Funded Warrants	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit
Preferred stock, beginning balance (in shares) at Dec. 31, 2021			0
Common stock, beginning balance (in shares) at Dec. 31, 2021				2,071,000
Treasury stock, beginning balance (in shares) at Dec. 31, 2021						8,000
Beginning balance at Dec. 31, 2021	$ 25,497,000		$ 0	$ 0		$ (181,000)	$ 227,584,000	$ (201,906,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(21,941,000)							(21,941,000)
Stock-based compensation	146,000						146,000
Forfeiture of unvested stock options	(85,000)						(85,000)
Series F Preferred Stock dividends	$ 0
Preferred stock, ending balance (in shares) at Dec. 31, 2022	1,930	0	0
Common stock, ending balance (in shares) at Dec. 31, 2022	2,071,000			2,071,000
Treasury stock, ending balance (in shares) at Dec. 31, 2022	8,000					8,000
Ending balance at Dec. 31, 2022	$ 3,617,000		$ 0	$ 0		$ (181,000)	227,645,000	(223,847,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(4,384,000)							(4,384,000)
Stock-based compensation	504,000			$ 180,000			504,000
Proceeds from private placement, net of fees (in shares)			6,550
Proceeds from private placement, net of fees	5,364,000						5,364,000
Proceeds from warrant exercise, net of fees (in shares)				339,000
Proceeds from warrant exercise, net of fees	534,000						534,000
Common stock exchanged for pre-funded warrants				(406,776)	(407,000)
Exercise of pre-funded warrants (in shares)				746,027	407,000
Conversions of Series F Preferred Stock (in shares)			(4,620)	14,102,477
Conversions of Series F Preferred Stock and accrued dividends	209,000			$ 2,000			207,000
Series F Preferred Stock dividends	$ (343,000)	$ (343,000)					(343,000)
Preferred stock, ending balance (in shares) at Dec. 31, 2023	1,930	1,930	1,930
Common stock, ending balance (in shares) at Dec. 31, 2023	16,692,124			16,692,000
Treasury stock, ending balance (in shares) at Dec. 31, 2023	8,000			7,553		8,000
Ending balance at Dec. 31, 2023	$ 5,501,000		$ 0	$ 2,000		$ (181,000)	$ 233,911,000	$ (228,231,000)