Note 5 - Intangible Assets (Details Textual)	3 Months Ended
	Jun. 30, 2021
Finite-Lived Intangible Assets, Remaining Amortization Period (Year)	6 years
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	10 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	15 years