Anti-Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share (Detail) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 28, 2012	Dec. 30, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share	21,207	12,441
6.75% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share	8,205
6.50% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share	3,165	3,165
Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share	3,728	3,140
Employee Stock Purchase Plan Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share		27
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of diluted net loss per share	6,109	6,109