Note 8 - Stockholders' Equity (Details Textual) - USD ($)					12 Months Ended
	Nov. 16, 2023	Jun. 21, 2023	Dec. 16, 2022	Apr. 12, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 06, 2023
Proceeds from Issuance of Common Stock					$ 4,388,000	$ 5,540,000
Payments of Stock Issuance Costs					$ 662,000	$ 418,000
November 2023 Financing [Member]
Stock Issued During Period, Shares, New Issues (in shares)	2,000,000
Shares Issued, Price Per Share (in dollars per share)	$ 0.65
Proceeds from Issuance of Common Stock	$ 1,300,000
Payments of Stock Issuance Costs	$ 312,000
June 2023 Financing [Member]
Stock Issued During Period, Shares, New Issues (in shares)		1,133,141
Shares Issued, Price Per Share (in dollars per share)		$ 2.336
Proceeds from Issuance of Common Stock		$ 2,600,000
Payments of Stock Issuance Costs		$ 194,000
June 2023 Financing [Member] | Company’s Directors and Executive Officers [Member]
Stock Issued During Period, Shares, New Issues (in shares)		203,337
Sales Agreement with Cantor Fitzgerald Co (Cantor) [Member]
Stock Issued During Period, Shares, New Issues (in shares)					215,224	711,511
Proceeds from Issuance of Common Stock					$ 441,000	$ 1,803,000
Payments of Stock Issuance Costs					179,000	$ 256,000
Sale of Stock, Aggregate Value, Maximum				$ 10,500,000
Accrued Sales Commission, Current, Percentage				3.00%
Sales Agreement With H.C. Wainwright & Co., LLC [Member]
Sale of Stock, Aggregate Value, Maximum					$ 2,750,000
Accrued Sales Commission, Current, Percentage							3.00%
Private Placement [Member] | Qualified Institutional Buyers and Institutional Accredited Investors [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,122,017
Shares Issued, Price Per Share (in dollars per share)			$ 1.68
Proceeds from Issuance of Common Stock			$ 3,400,000
Payments of Stock Issuance Costs			$ 162,000
Private Placement [Member] | Company’s Directors and Executive Officers [Member]
Stock Issued During Period, Shares, New Issues (in shares)			499,997