Note 6 - Restructuring - Activity Related to Restructuring Plans (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Accrued Restructuring				$ 7,610	$ 10,680
Restructuring charges		$ 546	$ 3,126	1,486	4,467
Costs paid or otherwise settled				(1,542)	(5,494)
Accrued Restructuring		7,554	9,653	7,554	9,653
Employee Severance [Member]
Accrued Restructuring	[1]			160	1,814
Restructuring charges	[1]			1,277	615
Costs paid or otherwise settled	[1]			(508)	(2,178)
Accrued Restructuring	[1]	929	251	929	251
Lease Termination and Fixed Assets [Member]
Accrued Restructuring				6,585	8,630
Restructuring charges				114	2,140
Costs paid or otherwise settled				(833)	(3,042)
Accrued Restructuring		5,866	7,728	5,866	7,728
Software Contracts and Engineering Tools [Member]
Accrued Restructuring	[2]			0	218
Restructuring charges	[2]			0	0
Costs paid or otherwise settled	[2]			0	(218)
Accrued Restructuring	[2]	0	0	0	0
Other Restructuring [Member]
Accrued Restructuring	[3]			865	18
Restructuring charges	[3]			95	1,712
Costs paid or otherwise settled	[3]			(201)	(56)
Accrued Restructuring	[3]	$ 759	$ 1,674	$ 759	$ 1,674

[1] Includes employee relocation and outplacement costs

[2] Includes cancellation of contracts, asset impairments, and accelerated depreciation on certain enterprise resource planning and customer relationship management systems

[3] Beginning in the second quarter of fiscal 2019, "Other" included termination fees on the cancellation of certain contracts under the Q2 2019 Sales Plan