Note 3 - Goodwill and Purchased Intangible Assets - Changes in Carrying Value of Goodwill (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 26, 2020	Dec. 28, 2019
Beginning balance		$ 238,669	$ 242,127
Additions			1,134
Impairments (1)	[1]		(715)
Impact of currency exchange		13,635	(3,877)
Ending balance		252,304	238,669
Semiconductor Test and Inspection [Member]
Beginning balance		218,775	220,808
Additions			2,117
Impairments (1)	[1]		(715)
Impact of currency exchange		11,949	(3,435)
Ending balance		230,724	218,775
PCB Test [Member]
Beginning balance		19,894	21,319
Additions			(983)
Impairments (1)	[1]		0
Impact of currency exchange		1,686	(442)
Ending balance		$ 21,580	$ 19,894

[1] Impairment of goodwill associated with our FSG segment that is presented as discontinued operations. This amount was not pushed down in the consolidated financial statements and was included within the balance of our Semiconductor Test & Inspection segment.