Summary of Significant Accounting Policies - Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								4 Months Ended	12 Months Ended
	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	May. 02, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jan. 31, 2015	Jan. 30, 2016	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss)	$ (3,062)	$ (1,274)	$ (2,682)	$ 2,535	$ (2,485)	$ 5,476	$ 3,247	$ 4,259	$ (17,380)	$ (4,483)	$ 10,497	$ 23,943
Net income (loss) per share—Basic	$ (0.23)	$ (0.09)	$ (0.20)	$ 0.19	$ (0.18)	$ 0.41	$ 0.24	$ 0.32	$ (1.28)	$ (0.33)	$ 0.78	$ 1.80
Net income (loss) per share—Diluted	$ (0.23)	$ (0.09)	$ (0.20)	$ 0.19	$ (0.18)	$ 0.40	$ 0.24	$ 0.31	$ (1.28)	$ (0.33)	$ 0.77	$ 1.78
Average number of shares outstanding—Basic									13,541	13,596	13,451	13,272
Average number of shares outstanding—Diluted									13,541	13,596	13,572	13,439
Employee Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Incremental shares from the assumed exercise of outstanding stock options											73	108
Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Incremental shares from the assumed lapse of restrictions on restricted stock awards											48	59