Gross Carrying Amount and Accumulated Amortization of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 29, 2013	Sep. 28, 2012
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (50.7)	$ (48.5)
Net carrying amount	24.6	26.8
Developed Technology Rights
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	36.3	36.3
Patents, Licenses and Other
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	28.1	28.1
Customer contracts and supplier relationship
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	$ 10.9	$ 10.9