Customer-Funded Research & Development (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 26, 2013	Oct. 27, 2012	Oct. 26, 2013	Oct. 27, 2012
Customer-Funded Research & Development
Revenue from customer-funded R&D	$ 6.6	$ 10.4	$ 16.9	$ 17.0