Note 12 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net revenues	$ 18,871	$ 14,180
Earnings (loss) before income tax expense (benefit)	982	3,172
Net earnings (loss)	381	2,078
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(218)	(372)
Net earnings (loss)	(169)	(244)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	13,234	7,776
Earnings (loss) before income tax expense (benefit)	(92)	1,846
Net earnings (loss)	(455)	1,210
EMS [Member] | Operating Segments [Member]
Net revenues	5,637	6,404
Earnings (loss) before income tax expense (benefit)	1,292	1,698
Net earnings (loss)	$ 1,005	$ 1,112