Note 13 - Segment Information - Identifiable Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Identifiable Assets	$ 67,126	$ 62,030
Corporate, Non-Segment [Member]
Identifiable Assets	1,359	1,581
Thermal Testing Products [Member]
Identifiable Assets	52,096	50,782
EMS [Member]
Identifiable Assets	$ 13,671	$ 9,667