Stockholders Equity - Stock-Based Compensation Expense (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jul. 27, 2012	Jul. 29, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 79.2	$ 58.1
Cost of Goods Sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1.8	1.1
Cost of Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	5.6	3.9
Selling and Marketing Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	39.0	28.6
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	23.7	16.0
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 9.1	$ 8.5