Income Taxes (Reconciliation From The Federal Statutory Income Tax Rate To The Effective Income Tax Rate) (Details)	12 Months Ended
Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	24.50%	35.00%	35.00%
Impact from foreign operations	3.00%	(10.00%)	(5.00%)
State income taxes, net of federal benefit	0.00%	(1.00%)	0.00%
R&D tax credits	(10.00%)	(22.00%)	(16.00%)
Domestic production activities deduction	(2.00%)	(10.00%)	(2.00%)
Impact of U.S. Tax Act	(57.00%)	(0.00%)	(0.00%)
Acquisition costs	0.00%	(3.00%)	5.00%
Nondeductible stock option expense and other permanent items	2.00%	2.00%	1.00%
Effective income tax rate	(38.70%)	(9.00%)	18.00%

Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for qualified production activity.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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