Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Jan. 01, 2016	Jan. 02, 2015
Income Tax Disclosure [Abstract]
Purchased intangibles	$ 122.6	$ 143.3
Depreciation and amortization	11.0	11.3
US residual tax on foreign earnings	12.2	12.3
Other	0.0	0.3
Total deferred tax liabilities	145.8	167.2
Inventory valuation differences	11.5	9.8
Expenses not currently deductible	26.2	26.2
US federal tax credit carryforwards	0.6	0.4
Deferred revenue	6.6	4.5
US state tax credit carryforwards	16.4	15.7
Accrued warranty	3.4	3.8
US federal net operating loss carryforwards	5.5	7.9
Foreign net operating loss carryforwards	41.7	29.7
Stock-based compensation	29.6	21.8
Other	9.0	5.3
Total deferred tax assets	150.5	125.1
Valuation allowance	(34.9)	(29.3)
Total deferred tax assets	115.6	95.8
Total deferred tax liabilities	(30.2)	(71.4)
Current deferred income tax assets	0.0	45.6
Non-current deferred income tax assets	21.5	5.0
Current deferred income tax liabilities	0.0	(0.9)
Non-current deferred income tax liabilities	$ (51.7)	$ (121.1)