Note 5 - Revenue From Contracts With Customers - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended														12 Months Ended
	Dec. 31, 2020	[1]	Sep. 30, 2020	[2]	Jun. 30, 2020	[3]	Mar. 31, 2020	[4]	Dec. 31, 2019	Sep. 30, 2019	[5]	Jun. 30, 2019	[6]	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Net revenues	$ 14,875		$ 14,443		$ 13,275		$ 11,230		$ 13,614	$ 14,632		$ 14,352		$ 18,062	$ 53,823	$ 60,660
Semiconductor Market [Member]
Net revenues															26,870	30,953
Industrial Market [Member]
Net revenues															17,341	21,231
Defense/ Aerospace [Member]
Net revenues															6,314	4,842
Telecommunications Market [Member]
Net revenues															1,715	1,845
Other Multi Markets [Member]
Net revenues															1,583	1,789
Thermal Testing Products [Member]
Net revenues															15,768	17,631
Thermal Process [Member]
Net revenues															18,966	20,079
Semiconductor Production Test Products [Member]
Net revenues															13,112	16,273
Service and Other Products [Member]
Net revenues															5,977	6,677
End User [Member]
Net revenues															48,041	55,074
OEM and Integrators [Member]
Net revenues															$ 5,782	$ 5,586

[1] The quarter ended December 31, 2020 includes $1,078 of restructuring and other charges which are discussed in Note 3.

[2] The quarter ended September 30, 2020 includes $161 of restructuring and other charges which are discussed in Note 3.

[3] The quarter ended June 30, 2020 includes $38 of restructuring and other charges which are discussed in Note 3.

[4] The quarter ended March 31, 2020 includes $8 of restructuring and other charges which are discussed in Note 3.

[5] The quarter ended September 30, 2019 includes $17 of restructuring and other charges which are discussed in Note 3.

[6] The quarter ended June 30, 2019 includes $223 of restructuring and other charges which are discussed in Note 3.