Stockholders' Equity And Stock-Based Compensation (Schedule of Stock-Based Compensation By Classification) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Recognized tax benefit from the exercise of ISO and ESPP	$ 353	$ 577	$ 802
Stock-based compensation expense	76,580	71,249	65,343
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	12,884	12,595	18,959
Allocated Share-based Compensation Expense, Net of Tax	63,696	58,654	46,384
Cost of products and services [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,710	1,574	1,458
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	23,191	19,515	18,497
Sales and marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	28,137	24,997	26,175
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 23,542	$ 25,163	$ 19,213

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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