Statements of Stockholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member] January 2022 Public Offering [Member]	Preferred Stock [Member] Series D Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member] January 2022 Public Offering [Member]	Common Stock [Member] Series D Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] January 2022 Public Offering [Member]	Additional Paid-in Capital [Member] Series D Preferred Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member] January 2022 Public Offering [Member]	Retained Earnings [Member] Series D Preferred Stock [Member]	Retained Earnings [Member]	January 2022 Public Offering [Member]	Series D Preferred Stock [Member]	Total
Balance at December 31, 2020 (in shares) at Dec. 31, 2020			52,369			4,246,308
Balance at December 31, 2020 at Dec. 31, 2020						$ 4			$ 380,413			$ (367,341)			$ 13,076
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)			0			500,000
Issuance of common stock in public offerings, net of commissions and issuance costs						$ 1			13,043			0			13,043
Conversion of Series B preferred stock into common stock (in shares)			(93)			18,600
Issuance of common stock upon vesting of restricted stock units (in shares)			0			13,355
Employee stock-based compensation						$ 0			1,015			0			1,015
Issuance of Series A preferred stock to pay dividends (in shares)			4,175			0
Issuance of Series A preferred stock to pay dividends						$ 0			4,175			0			4,175
Accretion of Series A preferred stock dividends						0			(4,175)			0			(4,175)
Net and comprehensive loss						$ 0			0			(17,412)			(17,412)
Balance at December 31, 2021 (in shares) at Dec. 31, 2021			56,451			4,778,263
Balance at December 31, 2021 at Dec. 31, 2021						$ 5			394,471			(384,753)			9,723
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)	0	7,600		1,285,603	0
Issuance of common stock in public offerings, net of commissions and issuance costs				$ 1	$ 0		$ 5,195	$ 6,721		$ 0	$ 0		$ 5,196	$ 6,721
Conversion of Series B preferred stock into common stock (in shares)			(7,600)			950,000
Issuance of common stock upon vesting of restricted stock units (in shares)			0			8,590
Employee stock-based compensation						$ 0			127			0			127
Issuance of Series A preferred stock to pay dividends (in shares)			4,510			0
Issuance of Series A preferred stock to pay dividends						$ 0			4,510			0			4,510
Accretion of Series A preferred stock dividends						0			(4,510)			0			(4,510)
Net and comprehensive loss						0			0			(17,623)			(17,623)
Conversion of Series D preferred stock into common stock						$ 1			0			0			1
Exercise of pre-funded warrants for common stock (in shares)			0			784,019
Exercise of pre-funded warrants for common stock						$ 1			0			0			1
Reclassifications and adjustments due to rounding impact from reverse stock split for fractional shares (in shares)			0			26,169
Reclassifications and adjustments due to rounding impact from reverse stock split for fractional shares						$ 0			0			0			0
Issuance of common stock upon vesting of restricted stock units						$ 0			0			0			0
Balance at December 31, 2021 (in shares) at Dec. 31, 2022			60,961			7,832,644
Balance at December 31, 2021 at Dec. 31, 2022						$ 8			$ 406,514			$ (402,376)			$ 4,146