Goodwill and Intangible Assets - Gross Carrying Amount and Accumulated Amortization of Intangible Assets (Detail) - USD ($) $ in Millions	Oct. 02, 2015	Sep. 26, 2014
Finite Lived Intangible Assets [Line Items]
Accumulated amortization	$ (65.1)	$ (56.9)
Net carrying amount	62.0	38.9
Acquired existing technology
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets:	71.7	54.6
Patents, licenses and other
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets:	35.3	28.8
Customer contracts and supplier relationship
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets:	$ 20.1	$ 12.4