Note 1 - Summary of Significant Accounting Policies - Reported Share-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Allocated share-based compensation	$ 3,403	$ 3,662	$ 7,014	$ 7,355
Income tax benefit	(223)	(79)	(395)	(359)
Total share-based compensation, net	3,180	3,583	6,619	6,996
Cost of Sales [Member]
Allocated share-based compensation	211	208	423	333
Research and Development Expense [Member]
Allocated share-based compensation	828	776	1,661	1,414
Selling, General and Administrative Expenses [Member]
Allocated share-based compensation	$ 2,364	$ 2,678	$ 4,930	$ 5,608

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=120381028&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=120381028&loc=d3e5070-113901

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