Note 10 - License Agreements (Details Textual)		12 Months Ended
	Dec. 31, 2022	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Statement [Line Items]
Number Of License Agreements		3
Number Of Expired License Agreements	1
Revenue from Contract with Customer, Excluding Assessed Tax		$ 7,177,000	$ 8,206,000
License, Excluding Sell-off Agreements [Member
Statement [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		373,000
License [Member]
Statement [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,102,000	265,000
License [Member] | Sell-off Agreements With Customers [Member]
Statement [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 730,000	$ 0