Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 26, 2015	Jun. 27, 2014	Jun. 26, 2015	Jun. 27, 2014
Income Taxes [Line Items]
(Benefit) provision for income taxes	$ 129,000	$ 115,000	$ 100,000	$ 266,000
Effective tax rates	(78.70%)		2.20%
Decrease in unrecognized tax benefits	$ 0		$ (201,000)
Other Current Assets
Income Taxes [Line Items]
Decrease in unrecognized tax benefits			(117,000)
Other Assets
Income Taxes [Line Items]
Decrease in unrecognized tax benefits			(457,000)
Other Long-term Liabilities
Income Taxes [Line Items]
Decrease in unrecognized tax benefits			$ (574,000)
Minimum
Income Taxes [Line Items]
Statutes of limitations expiration period			3 years
Maximum
Income Taxes [Line Items]
Statutes of limitations expiration period			5 years