Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Acquired Goodwill Activity (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 30, 2019		Dec. 29, 2018
Balance		$ 242,127	[1]	$ 65,613
Additions, net				179,263
Impact of currency exchange		(2,857)		(2,749)
Balance		239,270		242,127	[1]
Semiconductor Test and Inspection [Member]
Balance	[2]	220,808		65,613
Additions, net	[2]			157,661
Impact of currency exchange	[2]	(1,827)		(2,466)
Balance	[2]	218,981		220,808
PCB Test [Member]
Balance		21,319
Additions, net				21,602
Impact of currency exchange		(1,030)		(283)
Balance		$ 20,289		$ 21,319

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

[2] 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.