Note 3 - Revenue Recognition 1 (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Revenue, Performance Obligation Satisfied, Revenue Recognized, Percentage	79.00%	78.00%	76.00%	79.00%
Minimum [Member]
Warranty Period (Year)			1 year
Contract with Customer, Payment Term (Day)			30 days
Maximum [Member]
Warranty Period (Year)			3 years
Extended Service Warranty, Term (Year)			4 years
Contract with Customer, Payment Term (Day)			60 days
Grant [Member]
Revenues, Total	$ 0.1	$ 1.1	$ 0.9	$ 1.8