Note 11 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net revenues	$ 18,062	$ 18,871
Earnings (loss) before income tax expense (benefit)	1,462	982
Net earnings (loss)	1,138	381
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(729)	(218)
Net earnings (loss)	(568)	(169)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	12,634	13,234
Earnings (loss) before income tax expense (benefit)	1,144	(92)
Net earnings (loss)	891	(455)
EMS [Member] | Operating Segments [Member]
Net revenues	5,428	5,637
Earnings (loss) before income tax expense (benefit)	1,047	1,292
Net earnings (loss)	$ 815	$ 1,005