Stockholders' Equity And Stock-Based Compensation (Schedule Of Stock-Based Compensation Expense By Plan) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 25, 2020
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	$ 32,656	$ 26,313
Benefit from income taxes	(5,119)	(4,212)
Total stock-based compensation, net of tax	27,537	22,101
Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	3,305	4,486
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	27,720	20,393
Employee Stock Purchase Plan [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	1,631	1,434
Cost of Sales [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	590	634
Research and Development Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	10,102	7,933
Selling and Marketing Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	12,248	9,796
General and Administrative Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	$ 9,716	$ 7,950