Note 14 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Net revenues	$ 21,820		$ 13,275		$ 41,376	$ 24,505
Earnings (loss) before income tax expense (benefit)	3,056		183		5,634	(1,210)
Net earnings (loss)	2,609	$ 2,212	170	$ (1,143)	4,821	(973)
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(836)		(65)		(981)	(28)
Net earnings (loss)	(715)		(53)		(839)	(22)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	12,766		9,476		23,821	18,810
Earnings (loss) before income tax expense (benefit)	1,023		(13)		1,126	(439)
Net earnings (loss)	875		(3)		963	(353)
EMS [Member] | Operating Segments [Member]
Net revenues	9,054		3,799		17,555	5,695
Earnings (loss) before income tax expense (benefit)	2,869		261		5,489	(743)
Net earnings (loss)	$ 2,449		$ 226		$ 4,697	$ (598)