Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 26, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Research and development asset acquired fair value	$ 8.8	$ 10.6
Amortization expense for intangible assets	15.6	$ 8.4	$ 4.8
Future amortization expense, fiscal year 2017	20.1
Future amortization expense, fiscal year 2018	18.3
Future amortization expense, fiscal year 2019	14.1
Future amortization expense, fiscal year 2020	12.7
Future amortization expense, fiscal year 2021	9.5
Future amortization expense, thereafter	$ 21.2