Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 30, 2016	Jan. 01, 2016
Income Tax Disclosure [Abstract]
Purchased intangibles	$ 91.9	$ 122.6
Depreciation and amortization	11.7	11.0
US residual tax on foreign earnings	11.3	12.2
Total deferred tax liabilities	114.9	145.8
Inventory valuation differences	12.9	11.5
Expenses not currently deductible	27.7	26.2
US federal tax credit carryforwards	0.3	0.6
Deferred revenue	6.9	6.6
US state tax credit carryforwards	15.1	16.4
Accrued warranty	3.1	3.4
US federal net operating loss carryforwards	3.8	5.5
Foreign net operating loss carryforwards	31.2	41.7
Stock-based compensation	31.9	29.6
Other	4.1	9.0
Total deferred tax assets	137.0	150.5
Valuation allowance	(30.6)	(34.9)
Total deferred tax assets	106.4	115.6
Total deferred tax liabilities	(8.5)	(30.2)
Non-current deferred income tax assets	30.3	21.5
Non-current deferred income tax liabilities	$ (38.8)	$ (51.7)