Stock Plans (Summary of Total Compensation Recognized Related to Outstanding Stock Options) (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 05, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	$ 3,050	$ 6,097
Cost of sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	254	334
Research and development expenses [Member ]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	272	291
Selling, general and administrative and other expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	$ 2,524	$ 5,472

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration