Note 1 - Summary of Significant Accounting Policies - Reported Share-based Compensation in Consolidated Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 27, 2021	Mar. 28, 2020
Share-based compensation of continuing operations	$ 3,523	$ 3,611
Income tax benefit	(234)	(172)
Total share-based compensation, net	3,289	3,439
Cost of Sales [Member]
Share-based compensation of continuing operations	262	212
Research and Development Expense [Member]
Share-based compensation of continuing operations	781	833
Selling, General and Administrative Expenses [Member]
Share-based compensation of continuing operations	$ 2,480	$ 2,566

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
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-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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