Note J - Business Segments and Foreign Operations - Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Net Sales	$ 218,581	$ 246,838
Long-lived assets	63,455	76,724
Reportable Geographical Components [Member] | UNITED STATES
Net Sales	64,344	83,771
Long-lived assets	34,629	41,996
Reportable Geographical Components [Member] | NETHERLANDS
Net Sales	33,026	39,501
Long-lived assets	12,447	12,659
Reportable Geographical Components [Member] | BELGIUM
Long-lived assets	8,575	8,363
Reportable Geographical Components [Member] | CHINA
Net Sales	25,790	26,354
Reportable Geographical Components [Member] | ITALY
Net Sales	16,041	11,802
Long-lived assets	1,525	1,697
Reportable Geographical Components [Member] | AUSTRALIA
Net Sales	17,963	12,438
Reportable Geographical Components [Member] | SWITZERLAND
Long-lived assets	503	6,804
Reportable Geographical Components [Member] | Other Countries [Member]
Net Sales	53,619	60,420
Long-lived assets	5,776	5,205
Reportable Geographical Components [Member] | AUSTRIA
Net Sales	$ 7,798	$ 12,552