Summary of Acquired Intangible Assets (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 26, 2016	Dec. 27, 2015
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Gross Carrying Amount	$ 365.9	$ 365.3
Total identifiable intangible assets, Accumulated Amortization	(341.9)	(337.8)
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Gross Carrying Amount	260.6	260.1
Total identifiable intangible assets, Accumulated Amortization	$ (249.7)	(248.1)
Developed Technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	8 years
Developed Technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	10 years
Customer Base
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Gross Carrying Amount	$ 85.8	85.7
Total identifiable intangible assets, Accumulated Amortization	$ (82.6)	(80.9)
Customer Base | Minimum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	6 years
Customer Base | Maximum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	10 years
Core Technology
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Gross Carrying Amount	$ 15.7	15.7
Total identifiable intangible assets, Accumulated Amortization	$ (8.0)	(7.4)
Core Technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	10 years
Core Technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	15 years
In Process R&D
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Gross Carrying Amount	$ 3.3	3.3
Total identifiable intangible assets, Accumulated Amortization	$ (1.4)	(1.2)
In Process R&D | Minimum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	3 years
In Process R&D | Maximum
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	10 years
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets, Period of Amortization	5 years
Total identifiable intangible assets, Gross Carrying Amount	$ 0.5	0.5
Total identifiable intangible assets, Accumulated Amortization	$ (0.2)	$ (0.2)