Note 7 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020	Jan. 02, 2021
Operating Lease, Right-of-Use Asset	$ 26,430		$ 26,430		$ 22,178
Operating Lease, Weighted Average Remaining Lease Term (Year)	4 years 7 months 6 days		4 years 7 months 6 days
Operating Lease, Weighted Average Discount Rate, Percent	5.30%		5.30%
Operating Lease, Cost	$ 2,000	$ 1,900	$ 3,900	$ 3,800
Operating Lease Liability for Previously Restructured Facilities	7,700		7,700
Operating Lease, Liability, Total	27,268		27,268		$ 23,055
Hillsboro, Oregon and Shanghai, China Facility Leases [Member]
Operating Lease, Right-of-Use Asset	7,200		7,200
Operating Lease, Liability, Total	$ 7,200		$ 7,200