Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Acquired Goodwill Activity (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 29, 2019		Dec. 29, 2018
Balance		$ 242,127	[1]	$ 65,613
Additions, net				179,263
Impact of currency exchange		(1,359)		(2,749)
Adjustments	[2]	698
Balance		241,466		242,127	[1]
Semiconductor Test and Inspection [Member]
Balance	[3]	220,808		65,613
Additions, net	[3]			157,661
Impact of currency exchange	[3]	(1,377)		(2,466)
Adjustments	[2],[3]	1,681
Balance	[3]	221,112		220,808
PCB Test [Member]
Balance		21,319
Additions, net				21,602
Impact of currency exchange		18		(283)
Adjustments	[2]	(983)
Balance		$ 20,354		$ 21,319

[1] Derived from December 29, 2018 audited financial statements

[2] Amounts represent adjustments to the preliminary goodwill from the Xcerra acquisition.

[3] After the acquisition of Xcerra on October 1, 2018 we report in two segments, Semiconductor Test & Inspection and PCB Test. Prior year amounts would have been reported in our Semiconductor Test & Inspection segment and have been presented accordingly.