Note 9 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 25, 2021
Inventory, receivable and warranty reserves	$ 13,599	$ 12,166
Net operating loss carryforwards	39,545	44,806
Tax credit carryforwards	29,646	31,264
Capitalized R&D	19,819	8,728
Accrued employee benefits	4,416	5,695
Stock-based compensation	2,990	2,222
Lease liabilities	3,965	4,500
Other	472	2,674
Gross deferred tax assets	114,452	112,055
Less valuation allowance	(89,234)	(76,250)
Total deferred tax assets	25,218	35,805
Intangible assets and other acquisition basis differences	38,921	48,657
Operating lease right-of-use assets	3,573	4,066
Unremitted earnings of foreign subsidiaries	153	4,207
Total deferred tax liabilities	42,647	56,930
Net deferred tax liabilities	(17,429)	(21,125)
Other assets (long-term)	3,930	4,762
Long-term deferred income tax liabilities	$ (21,359)	$ (25,887)