Note 13 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net revenues	$ 19,556	$ 11,230
Earnings (loss) before income tax expense (benefit)	2,578	(1,393)
Net earnings (loss)	2,212	(1,143)
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(145)	37
Net earnings (loss)	(124)	31
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	11,055	9,334
Earnings (loss) before income tax expense (benefit)	103	(426)
Net earnings (loss)	88	(350)
EMS [Member] | Operating Segments [Member]
Net revenues	8,501	1,896
Earnings (loss) before income tax expense (benefit)	2,620	(1,004)
Net earnings (loss)	$ 2,248	$ (824)