Note 5 - Restructuring Charges (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Restructuring Charges, Total	$ 7,623	$ 13,484	$ 18,704
Integration Program [Member]
Restructuring Charges, Total	11,354	16,213	37,757
Integration Program [Member] \| Employee Severance [Member]
Restructuring Charges, Total	$ 6,485	$ 12,170	17,791
Integration Program [Member] \| Employee Severance [Member] \| Executive Officers and Board of Directors of Xcerra [Member]
Restructuring Charges, Total			8,200
Integration Program [Member] \| Severance and Other Separation Payments [Member]
Business Combination, Contingent Consideration, Liability, Total			$ 6,900

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration