Note 2 - Summary of Significant Accounting Policies - Estimated Useful Lives of Intangible Assets (Details)	12 Months Ended
	Mar. 31, 2022
Patents (Year)
Patents (Year)	20 years
Licensing Agreements [Member] | Minimum [Member]
Patents (Year)	8 years
Licensing Agreements [Member] | Maximum [Member]
Patents (Year)	14 years