Certain Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 128,790	$ 143,845
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(106,469)	(114,580)
Property, Plant and Equipment, Net	22,321	29,265
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	75,094	87,121
Capitalized software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	32,696	35,139
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	14,951	15,051
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 6,049	$ 6,534