Note 4 - Revenue From Contracts With Customers - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net revenues	$ 13,275	$ 14,352	$ 24,505	$ 32,414
Semiconductor Market [Member]
Net revenues	6,858	7,641	11,869	17,752
Industrial Market [Member]
Net revenues	3,899	4,279	8,126	10,225
Defense/ Aerospace [Member]
Net revenues	1,496	1,150	2,904	2,132
Telecommunications Market [Member]
Net revenues	597	691	1,008	1,284
Other Multi Markets [Member]
Net revenues	425	591	598	1,021
Thermal Testing Products [Member]
Net revenues	3,703	4,282	7,850	9,249
Thermal Process [Member]
Net revenues	4,563	4,660	8,311	10,668
Semiconductor Production Test Products [Member]
Net revenues	3,665	3,609	5,489	8,893
Service and Other Products [Member]
Net revenues	1,344	1,801	2,855	3,604
End User [Member]
Net revenues	11,946	13,106	21,867	29,143
OEM and Integrators [Member]
Net revenues	$ 1,329	$ 1,246	$ 2,638	$ 3,271