Note 12 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net revenues	$ 11,230	$ 18,062
Earnings (loss) before income tax expense (benefit)	(1,393)	1,462
Net earnings (loss)	(1,143)	1,138
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	37	(729)
Net earnings (loss)	31	(568)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	9,334	12,634
Earnings (loss) before income tax expense (benefit)	(426)	1,144
Net earnings (loss)	(350)	891
EMS [Member] | Operating Segments [Member]
Net revenues	1,896	5,428
Earnings (loss) before income tax expense (benefit)	(1,004)	1,047
Net earnings (loss)	$ (824)	$ 815