Operating Segments and Geographic Data (Schedule Of Concentration Of Revenue From Individual Geographic Regions) (Details)	12 Months Ended
	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	100.00%	100.00%	100.00%
U.S. [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
South Korea [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
Japan [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
Europe [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
Taiwan [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
China [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%
Other [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	0.00%	0.00%	0.00%