Note 5 - Revenue From Contracts With Customers - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net revenues	$ 14,443	$ 14,632	$ 38,948	$ 47,046
Semiconductor Market [Member]
Net revenues	7,387	7,126	19,256	24,878
Industrial Market [Member]
Net revenues	4,220	5,758	12,346	15,983
Defense/ Aerospace [Member]
Net revenues	2,015	153	4,919	1,437
Telecommunications Market [Member]
Net revenues	419	1,377	1,427	3,509
Other Multi Markets [Member]
Net revenues	402	218	1,000	1,239
Thermal Testing Products [Member]
Net revenues	3,632	4,568	11,482	13,817
Thermal Process [Member]
Net revenues	5,574	4,635	13,885	15,303
Semiconductor Production Test Products [Member]
Net revenues	3,604	3,841	9,093	12,734
Service and Other Products [Member]
Net revenues	1,633	1,588	4,488	5,192
End User [Member]
Net revenues	12,651	13,167	34,518	42,310
OEM and Integrators [Member]
Net revenues	$ 1,792	$ 1,465	$ 4,430	$ 4,736