Stockholders' Equity And Stock-Based Compensation (Schedule Of Stock-Based Compensation Expense By Plan) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 25, 2021	Jun. 26, 2020	Jun. 25, 2021	Jun. 26, 2020
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	$ 24,836	$ 21,285	$ 75,562	$ 64,850
Benefit from income taxes	(3,944)	(3,392)	(12,015)	(10,507)
Total stock-based compensation, net of tax	20,892	17,893	63,547	54,343
Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	3,203	4,053	10,913	12,573
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	20,348	15,983	60,594	48,800
Employee Stock Purchase Plan [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	1,285	1,249	4,055	3,477
Cost of Sales [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	426	505	1,549	1,555
Research and Development Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	7,296	6,202	22,419	19,368
Selling and Marketing Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	9,286	7,892	28,192	23,768
General and Administrative Expense [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock-based compensation expense	$ 7,828	$ 6,686	$ 23,402	$ 20,159