Note 6 - Goodwill and Intangible Assets - Component of Goodwill (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Dec. 21, 2021
Goodwill	$ 21,863	$ 21,448
Environmental Technologies [Member]
Goodwill	1,817	1,817
Process Technologies [Member]
Goodwill	16,480	16,576
Acculogic [Member]
Goodwill			$ 3,363
Acculogic [Member] | Electronic Test [Member]
Goodwill	3,566	3,055
Sigma [Member] | Environmental Technologies [Member]
Goodwill	1,656	1,656
Thermonics [Member] | Environmental Technologies [Member]
Goodwill	50	50
Z-Sciences [Member] | Environmental Technologies [Member]
Goodwill	111	111
Ambrell [Member] | Process Technologies [Member]
Goodwill	12,032	12,032
Videology [Member] | Process Technologies [Member]
Goodwill	$ 4,448	$ 4,544