Summary of Acquired Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 25, 2011
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Gross Carrying Amount	$ 359.4	$ 359.3
Goodwill	169.3	169.3
Identifiable intangible assets, Accumulated Amortization	(307.6)	(293.9)
Identifiable intangible assets, including goodwill, Gross Carrying Amount	528.7	528.6
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Gross Carrying Amount	250.8	250.7
Identifiable intangible assets, Accumulated Amortization	(225.0)	(214.3)
Developed Technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	2 years
Developed Technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	15 years
Customer Base
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Gross Carrying Amount	81.6	81.6
Identifiable intangible assets, Accumulated Amortization	(70.4)	(68.5)
Customer Base | Minimum
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	8 years
Customer Base | Maximum
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	10 years
Core Technology
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	10 years
Identifiable intangible assets, Gross Carrying Amount	15.7	15.7
Identifiable intangible assets, Accumulated Amortization	(3.6)	(2.7)
In Process R&D
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	10 years
Identifiable intangible assets, Gross Carrying Amount	2.8	2.8
Identifiable intangible assets, Accumulated Amortization	(0.1)	0
Assembled Workforce
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	5 years
Identifiable intangible assets, Gross Carrying Amount	1.0	1.0
Identifiable intangible assets, Accumulated Amortization	(1.0)	(1.0)
Process Technology
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	5 years
Identifiable intangible assets, Gross Carrying Amount	1.6	1.6
Identifiable intangible assets, Accumulated Amortization	(1.6)	(1.6)
Patents
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets, Period of Amortization	4 years
Identifiable intangible assets, Gross Carrying Amount	5.9	5.9
Identifiable intangible assets, Accumulated Amortization	$ (5.9)	$ (5.8)