Note 9 - Stock-based Compensation - Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 03, 2021	Mar. 28, 2020
Total stock-based compensation	$ 10,454	$ 8,728
Cost of Sales [Member]
Total stock-based compensation	666	591
Research and Development Expense [Member]
Total stock-based compensation	2,767	2,594
Selling, General and Administrative Expenses [Member]
Total stock-based compensation	$ 7,021	$ 5,543

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

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