Note 6 - Restructuring (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Restructuring Charges, Total	$ 204	$ 546	$ 380	$ 1,486
Q1 2020 Plan [Member]
Restructuring Charges, Total		300		1,400
Restructuring and Related Cost, Cost Incurred to Date	2,000		2,000
Q1 2020 Plan [Member] | Maximum [Member]
Restructuring Charges, Total	100		100
Q2 2019 Sales Plan [Member]
Restructuring Charges, Total	0	200	0
Restructuring and Related Cost, Cost Incurred to Date	2,100		2,100
Q2 2019 Sales Plan [Member] | Maximum [Member]
Restructuring Charges, Total				100
June 2017 Plan [Member]
Restructuring Charges, Total	200	$ 100	400	$ 100
Restructuring and Related Cost, Cost Incurred to Date	21,300		21,300
June 2017 Plan [Member] | Maximum [Member]
Restructuring and Related Cost, Expected Cost, Total	23,500		23,500
June 2017 Plan [Member] | Minimum [Member]
Restructuring and Related Cost, Expected Cost, Total	$ 21,500		$ 21,500