Note 6 - Employee Benefit Plans - Reported Share-based Compensation in Consolidated Financial Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 25, 2021	Dec. 26, 2020
Share-based compensation of continuing operations	$ 14,918	$ 13,792	$ 14,234
Income tax benefit	(4,004)	(722)	(963)
Total share-based compensation, net of tax	10,914	13,070	13,271
Cost of Sales [Member]
Share-based compensation of continuing operations	646	828	893
Research and Development Expense [Member]
Share-based compensation of continuing operations	3,100	3,017	3,245
Selling, General and Administrative Expenses [Member]
Share-based compensation of continuing operations	$ 11,172	$ 9,947	$ 10,096