Note 6 - Restructuring - Activity Related to Restructuring Plans (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Restructuring charges		$ 204	$ 546	$ 380	$ 1,486
Employee Severance [Member]
Accrued Restructuring	[1]			246	160
Restructuring charges	[1]			17	1,277
Costs paid or otherwise settled	[1]			(10)	(508)
Accrued Restructuring	[1]	253	929	253	929
Lease Termination and Fixed Assets [Member]
Accrued Restructuring				8,233	6,585
Restructuring charges				363	114
Costs paid or otherwise settled				(896)	(833)
Accrued Restructuring		7,700	5,866	7,700	5,866
Software Contracts and Engineering Tools [Member]
Accrued Restructuring	[2]			664	865
Restructuring charges	[2]			0	95
Costs paid or otherwise settled	[2]			(664)	(201)
Accrued Restructuring	[2]	0	759	0	759
Other Restructuring [Member]
Accrued Restructuring				9,143	7,610
Restructuring charges				380	1,486
Costs paid or otherwise settled				(1,570)	(1,542)
Accrued Restructuring		$ 7,953	$ 7,554	$ 7,953	$ 7,554

[1] Includes employee relocation and outplacement costs.

[2] Includes termination fees on the cancellation of certain contracts under the Q2 2019 Sales Plan