Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 209,307,000	$ 212,618,000
Accumulated depreciation and amortization	(168,923,000)	(172,188,000)
Property and equipment, net	40,384,000	40,430,000
Depreciation expense	13,600,000	12,200,000	10,900,000
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	27,809,000
Computer and test equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	154,809,000	160,506,000
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8,755,000	9,363,000
Leasehold and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,460,000	$ 13,484,000