Note 12 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net revenues	$ 20,160	$ 17,352	$ 60,128	$ 47,420
Earnings (loss) before income tax expense (benefit)	162	2,841	5,540	8,349
Net earnings (loss)	(566)	2,018	3,829	5,541
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(447)	(292)	(1,055)	(1,841)
Net earnings (loss)	(352)	(186)	(867)	(1,158)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	14,616	11,470	41,849	28,440
Earnings (loss) before income tax expense (benefit)	(684)	1,539	1,816	4,735
Net earnings (loss)	(1,192)	1,183	768	3,228
EMS [Member] | Operating Segments [Member]
Net revenues	5,544	5,882	18,279	18,980
Earnings (loss) before income tax expense (benefit)	1,293	1,594	4,779	5,455
Net earnings (loss)	$ 978	$ 1,021	$ 3,928	$ 3,471