Note 7 - Commitments and Contingencies (Details Textual) - USD ($)	1 Months Ended				3 Months Ended				9 Months Ended
	Oct. 30, 2023	Sep. 30, 2023	Mar. 31, 2023	Feb. 28, 2022	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating Lease, Monthly Rent Payment		$ 4,700			$ 4,700				$ 4,700
Operating Lease, Rent Expense, Annual Increase In Rent, Percent		2.00%
Sublease Income					12,000			$ 12,000	37,000	$ 32,000
Operating Lease, Payments					34,000			21,000	109,000	91,000
License Agreements Expense					221,000			315,000	552,000	815,000
Stock Issued During Period, Value, New Issues						$ 69,000	$ 141,000
Houston Pharmaceuticals, Inc [Member]
Related Party Transaction, Amounts of Transaction					59,000			59,000	176,000	176,000
MD Anderson [Member]
License Agreements Expense					64,000			56,000	193,000	189,000
MD Anderson [Member] | Subsequent Event [Member]
Payments For Research And Development Agreement	$ 800,000
WPD Pharmaceuticals [Member] | License Termination [Member]
Payments for Termination of Commitment			$ 700,000
Stock Issued During Period, Value, New Issues			$ 800,000				$ 800,000
Stock Issued During Period, Shares, New Issues (in shares)			822,115				822,115
Exploration Invest Pte Ltd. (Exploration) [Member]
Payments for Termination of Commitment				$ 400,000
License Terminations Expense					$ 1,500,000			$ 400,000	$ 1,500,000	$ 400,000