Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income	Class A Common Stock	Class B Common Stock
Beginning Balance (in shares) at Feb. 02, 2013						10,772,000	16,920,000
Beginning Balance at Feb. 02, 2013	$ 117,296	$ 28	$ 117,391	$ (140)	$ 17
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18,137			18,137
Shares converted by founders (in shares)						278,000	(278,000)
Stock-based compensation expense	3,106		3,106
Restricted stock (in shares)						31,000
Exercise of stock options (in shares)						280,000
Exercise of stock options	2,389		2,389
Net change in unrealized gain (loss) on available-for-sale securities	(5)				(5)
Ending Balance (in shares) at Feb. 01, 2014						11,361,000	16,642,000
Ending Balance at Feb. 01, 2014	140,923	28	122,886	17,997	12
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,075			14,075
Shares converted by founders (in shares)						98,000	(98,000)
Stock-based compensation expense	3,499		3,499
Excess tax deficiencies from stock-based compensation	(124)		(124)
Restricted stock (in shares)						49,000
Exercise of stock options (in shares)						38,000
Exercise of stock options	304		304
Net change in unrealized gain (loss) on available-for-sale securities	9				9
Ending Balance (in shares) at Jan. 31, 2015						11,546,000	16,544,000
Ending Balance at Jan. 31, 2015	158,686	28	126,565	32,072	21
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,541			7,541
Shares converted by founders (in shares)						375,000	(375,000)
Stock-based compensation expense	3,926		3,926
Excess tax deficiencies from stock-based compensation	$ (35)		(35)
Restricted stock (in shares)						48,000
Exercise of stock options (in shares)	336,140					336,000
Exercise of stock options	$ 3,094		3,094
Net change in unrealized gain (loss) on available-for-sale securities	1				1
Ending Balance (in shares) at Jan. 30, 2016						12,305,000	16,169,000
Ending Balance at Jan. 30, 2016	$ 173,213	$ 28	$ 133,550	$ 39,613	$ 22