Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 144,851	$ 143,845
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(117,148)	(114,580)
Property, Plant and Equipment, Net	27,703	29,265
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	87,657	87,121
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	35,460	35,139
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	15,177	15,051
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 6,557	$ 6,534