Note 7 - Stockholders' Equity (Details Textual) - USD ($)				3 Months Ended	9 Months Ended
	Apr. 12, 2022	Mar. 29, 2021	Sep. 04, 2019	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Proceeds from Issuance of Common Stock					$ 1,658,000	$ 2,001,000
Payments of Stock Issuance Costs					$ 231,000	$ 59,000
Underwriters [Member]
Stock Issued During Period, Shares, New Issues			80,000
Purchase Agreement with Lincoln Park [Member]
Sale of Stock, Aggregate Value, Maximum		$ 20,000,000
Stock Issued During Period, Shares, New Issues		373,832
Shares Issued, Price Per Share		$ 5.35
Proceeds from Issuance of Common Stock		$ 2,000,000
Stock Issued During the Period, Shares, Commission Fees		80,000
Stock Issued During the Period, Commitment Shares Issued on Pro Rata Basis		5,000
Stock Issuable, Commitment Shares on Pro Rata Basis		5,000
Sales Agreement with Cantor Fitzgerald Co (Cantor) [Member]
Sale of Stock, Aggregate Value, Maximum	$ 10,500,000
Stock Issued During Period, Shares, New Issues				66,704	641,704
Proceeds from Issuance of Common Stock				$ 139,000	$ 1,700,000
Accrued Sales Commission, Current, Percentage	3.00%
Payments of Stock Issuance Costs				$ 1,000	$ 231,000