Note 11 - Accounts Payable and Accrued Expenses - Product Warranty Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Balance at beginning of period	$ 2,053	$ 2,015
Acquired warranty obligations	248	0
Change in accruals for warranties during the period	107	236
Settlements during the period	(222)	(83)
Balance at end of period	$ 2,186	$ 2,168