Note 4 - Revenue From Contracts With Customers - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net revenues	$ 11,230	$ 18,062
Semiconductor Market [Member]
Net revenues	5,011	10,111
Industrial Market [Member]
Net revenues	4,227	5,946
Defense/ Aerospace [Member]
Net revenues	1,408	982
Telecommunications Market [Member]
Net revenues	411	593
Other Non-semiconductors Markets [Member]
Net revenues	173	430
Thermal Testing Products [Member]
Net revenues	4,147	4,967
Thermal Process [Member]
Net revenues	3,748	6,009
Semiconductor Production Test Products [Member]
Net revenues	1,825	5,284
Service and Other Products [Member]
Net revenues	1,510	1,802
End User [Member]
Net revenues	9,922	16,037
OEM and Integrators [Member]
Net revenues	$ 1,308	$ 2,025