Note 3 - Revenue Recognition 1 (Details Textual) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue, Performance Obligation Satisfied, Revenue Recognized, Percentage	83.00%		86.00%	77.00%	82.00%
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			$ 300	$ 0	$ 800