Property and Equipment (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2017	Nov. 30, 2014	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross			$ 171,683	$ 184,267
Accumulated depreciation and amortization			(131,260)	(134,786)
Property and equipment, net			40,423	49,481	$ 51,852
Depreciation expense			16,300	18,400	18,100
Proceeds from sale of building			7,895	0	0
Gain on sale of building			4,624	0	0
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross			0	3,554
Buildings | Shanghai, China
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (1,400)
Property and equipment, net	3,600
Proceeds from sale of building	7,900
Direct selling costs	1,100
Gain on sale of building	$ (4,600)
Computer and test equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross			155,492	162,388
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross			2,914	3,460
Leasehold and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross			$ 13,277	$ 14,865
Land and Building
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 30,900
Accumulated depreciation and amortization		(17,900)
Proceeds from sale of building		14,600
Gain on sale of building		$ 1,600
Lease term		8 years
Restructuring
Property, Plant and Equipment [Line Items]
Depreciation expense					$ 1,500