Note 6 - Commitments and Contingencies (Details Textual) - USD ($)		1 Months Ended		3 Months Ended
	Apr. 30, 2023	Mar. 31, 2023	Feb. 28, 2022	Mar. 31, 2023	Mar. 31, 2022
Sublease Income				$ 12,000	$ 10,000
Operating Lease, Payments				38,000	35,000
License Agreements Expense				64,000	76,000
Research and Development Expense				5,687,000	4,620,000
Stock Issued During Period, Value, New Issues				141,000
MD Anderson [Member] | Sponsored Research [Member]
Research and Development Expense				155,000	187,000
MD Anderson [Member] | Subsequent Event [Member]
Payments For Research And Development Agreement	$ 700,000
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
Houston Pharmaceuticals, Inc [Member]
Related Party Transaction, Amounts of Transaction				$ 59,000	$ 59,000