Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 28, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares outstanding, Beginning	2,375
Number of Shares, Granted
Number of Shares, Exercised	(73)
Number of shares, Forfeited or Expired	(143)
Number of Shares outstanding, Ending	2,159
Vested and expected to vest	2,085
Number of shares, Exercisable	1,330
Weighted-Average Exercise Price, Beginning Balance	$ 6.71
Weighted-Average Exercise Price, Granted
Weighted-Average Exercise Price, Exercised	$ 2.10
Weighted-Average Exercise Price, Forfeited or Expired	$ 9.27
Weighted-Average Exercise Price, Ending Balance	$ 6.69
Weighted-Average Exercise Price, Vested and Expected to Vest	$ 6.69
Weighted-Average Exercise Price, Exercisable	$ 6.61
Weighted-Average Remaining Contractual Term, Beginning Balance	5 years 1 month 6 days
Weighted-Average Remaining Contractual Term, Ending Balance	5 years 2 months 12 days
Weighted-Average Remaining Contractual Term, Vested and Expected to vest	5 years 2 months 12 days
Weighted-Average Remaining Contractual Term, Exercisable	4 years 3 months 18 days
Aggregate Intrinsic Value, Beginning Balance	$ 648
Aggregate Intrinsic Value, Ending Balance	998
Aggregate Intrinsic Value, Vested and Expected to Vest	991
Aggregate Intrinsic Value, Exercisable	920
Service Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining Unrecognized Compensation Cost, Service-based	$ 2,245
Remaining Years to Vest, Service-based	10 months 24 days