Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 209,608,000	$ 209,307,000
Accumulated depreciation and amortization	(167,889,000)	(168,923,000)
Property and equipment, net	41,719,000	40,384,000
Depreciation expense	11,200,000	13,600,000	12,200,000
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,456,000	1,456,000
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	27,827,000	27,827,000
Computer and test equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	154,508,000	154,809,000
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,122,000	8,755,000
Leasehold and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,695,000	$ 16,460,000