Note 2 - Goodwill and Purchased Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 25, 2021	Dec. 26, 2020
Gross Carrying Amount, finite-lived intangible assets	$ 325,601	$ 338,279
Accumulated Amortization	134,435	112,412
Developed Technology Rights [Member]
Gross Carrying Amount, finite-lived intangible assets	237,525	239,250
Accumulated Amortization	$ 101,952	83,246
Remaining Useful Life (Year)	4 years 9 months 18 days
Customer Relationships [Member]
Gross Carrying Amount, finite-lived intangible assets	$ 66,662	74,933
Accumulated Amortization	$ 25,037	22,751
Remaining Useful Life (Year)	7 years 8 months 12 days
Trade Names [Member]
Gross Carrying Amount, finite-lived intangible assets	$ 21,096	23,756
Accumulated Amortization	$ 7,295	6,279
Remaining Useful Life (Year)	7 years 6 months
Noncompete Agreements [Member]
Gross Carrying Amount, finite-lived intangible assets	$ 318	340
Accumulated Amortization	$ 151	$ 136
Remaining Useful Life (Year)	5 years 3 months 18 days