Note 12 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net revenues	$ 21,097	$ 15,888	$ 39,968	$ 30,068
Earnings (loss) before income tax expense (benefit)	4,396	2,336	5,378	5,508
Net earnings (loss)	4,014	1,445	4,395	3,523
Corporate, Non-Segment [Member]
Earnings (loss) before income tax expense (benefit)	(390)	(1,177)	(608)	(1,549)
Net earnings (loss)	(346)	(728)	(515)	(972)
Thermal Testing Products [Member] | Operating Segments [Member]
Net revenues	13,999	9,194	27,233	16,970
Earnings (loss) before income tax expense (benefit)	2,592	1,350	2,500	3,196
Net earnings (loss)	2,415	835	1,960	2,045
EMS [Member] | Operating Segments [Member]
Net revenues	7,098	6,694	12,735	13,098
Earnings (loss) before income tax expense (benefit)	2,194	2,163	3,486	3,861
Net earnings (loss)	$ 1,945	$ 1,338	$ 2,950	$ 2,450