Note 5 - Acquired Intangible Assets and Goodwill - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Gross Carrying Amount	$ 56,392	$ 56,392
Accumulated Amortization	35,614	33,747
Patents [Member]
Gross Carrying Amount	24,715	24,715
Accumulated Amortization	24,068	23,860
Noncompete Agreements [Member]
Gross Carrying Amount	2,749	2,749
Accumulated Amortization	2,749	2,749
Customer Lists [Member]
Gross Carrying Amount	18,017	18,017
Accumulated Amortization	8,100	6,669
Trademarks [Member]
Gross Carrying Amount	9,736	9,736
Accumulated Amortization	266	174
Developed Technology Rights [Member]
Gross Carrying Amount	475	475
Accumulated Amortization	301	206
Licensing Agreements [Member]
Gross Carrying Amount	700	700
Accumulated Amortization	$ 130	$ 89