Note 14 - Subsequent Events (Details Textual) - Subsequent Event [Member] - USD ($) $ / shares in Units, $ in Millions	Nov. 09, 2023	Oct. 12, 2023	Oct. 11, 2023	Oct. 30, 2023	Oct. 10, 2023	Oct. 03, 2023
Inducement Warrant Shares [Member]
Warrants or Rights, Percent of Stock Purchasable			200.00%
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			56,249,080
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 0.1395	$ 0.01
Inducement Warrant Shares [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			56,249,080
Existing Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			28,124,540
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 0.1395	$ 0.01
Proceeds from Issuance or Sale of Equity			$ 3.9
Existing Warrants [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			28,124,540
The New Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				20,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)				$ 0.01
Licensing Agreement With Ardent [Member]
License Agreement, Initial Fee						$ 0.1
Fifth Amendment to License Agreement [Member]
License Agreement, Potential Development and Sales Milestone Payments and Royalties					$ 150.0
Revenue from Contract with Customer, Including Assessed Tax	$ 1.5	$ 1.5
License Agreement, Expected Payments					$ 1.5