Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $) In Millions	Apr. 29, 2011	Apr. 30, 2010
Income Taxes
Inventory reserves and capitalization	$ 6.6	$ 5.1
Reserves and accruals not currently deductible	50.2	49.1
Net operating loss and credit carryforwards	120.3	75.3
Stock-based compensation	74.1	90.2
Deferred revenue	176.2	168.7
Capitalized research and development expenditures	3.3	6.6
Investment losses	0	2.4
Conditional royalty	13.6	13.6
Other	0.5	1.0
Gross deferred tax assets	444.8	412.0
Valuation allowance	(45.5)	(28.3)
Total deferred tax assets	399.3	383.7
Depreciation	11.9	8.0
Acquisition intangibles	7.4	8.5
Convertible notes	28.2	35.2
Other	(1.9)	(1.0)
Total deferred tax liabilities	45.6	50.7
Net deferred tax assets	$ 353.7	$ 333.0