Note 5 - Revenue (Details Textual) - USD ($)	1 Months Ended	3 Months Ended
	Jul. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Jan. 12, 2024	Dec. 31, 2023	Nov. 30, 2022
Revenues		$ 2,181,000	$ 675,000
Income Tax Expense (Benefit)		45,000	29,000
Government Contract Receivable, Unbilled Amounts		$ 1,596,000			$ 0
Deferred Revenue, Current						$ 2,000,000
Foreign Tax Jurisdiction [Member] | National Tax Agency, Japan [Member]
Royalty Withholding Tax		5.00%
Income Tax Expense (Benefit)		$ 29,000	14,000
Royalty [Member] | Daiichi Sankyo Collaberation and License Agreement [Member]
Royalty Percentage		4.00%
Revenues		$ 0	0
Non Cash Royalty Revenue [Member]
Revenues		585,000	278,000
Non Cash Royalty Revenue [Member] | Daiichi Sankyo Collaberation and License Agreement [Member]
Revenues		600,000	300,000
Government Contract [Member]
Revenues		1,596,000	0
Government Assistance, Award Amount				$ 9,300,000
Government Contract Receivable, Unbilled Amounts		1,600,000
Grant [Member]
Revenues		$ 0	$ 397,000
Grants Receivable						$ 3,500,000
Grant Milestone Completion [Member]
Revenues	$ 1,500,000