Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common stock [Member]	Additional Paid-in Capital [Member]	Accumulated deficit [Member]	Unrestricted stock [Member]
Balance at Feb. 01, 2014	$ 116,873	$ 542	$ 284,622	$ (168,291)
Balance, common stock, shares at Feb. 01, 2014		54,190,724
Share-based compensation expense	5,757		5,757
Issuance of unrestricted stock awards	160	$ 0	160
Issuance of unrestricted stock awards (in shares)					4,324
Exercise of options and warrants to purchase common stock	1,481	$ 2	1,479
Exercise of options and warrants to purchase common stock (in shares)		207,809
Vesting of restricted shares related to stock option exercises	61		61
Vesting of restricted stock units	0		0
Vesting of restricted stock units (in shares)		(22,286)
Issuance of common stock (in shares)		(87)
Stock Issued During Period, Value, New Issues	(1)	$ 0	(1)
Stock Issued During Period, Value, Conversion of Convertible Securities	(314)	$ 0	(314)
Stock Issued During Period, Shares, Conversion of Convertible Securities		(9,173)
Excess tax benefit	2,049		2,049
Issuance of common stock to employees under employee stock purchase plan	179		179
Issuance of common stock to employees under employee stock purchase plan (in shares)		4,345
Net income	48,024			48,024
Balance at Jan. 31, 2015	174,269	$ 544	293,992	(120,267)
Balance, common stock, shares at Jan. 31, 2015		54,420,228.000
Net Income (Loss) Available to Common Stockholders, Basic	48,004
Issuance of unrestricted stock awards	10,876	$ 0	10,876
Issuance of unrestricted stock awards (in shares)		0
Exercise of options and warrants to purchase common stock	912	$ 2	910
Exercise of options and warrants to purchase common stock (in shares)		115,364
Issuance of common stock (in shares)		(51,546)			(7,947)
Common shares withheld for taxes	(322)		(322)
Common shares withheld for taxes (in shares)		(9,462)
Stock Issued During Period, Value, New Issues	(280)		(280)
Excess tax benefit	608		608
Issuance of common stock to employees under employee stock purchase plan	178		178
Issuance of common stock to employees under employee stock purchase plan (in shares)		5,018
Net income	57,680			57,680
Balance at Jan. 30, 2016	$ 244,481	$ 546	306,522	(62,587)
Balance, common stock, shares at Jan. 30, 2016	54,590,641	54,590,641.000
Net Income (Loss) Available to Common Stockholders, Basic	$ 57,680
Issuance of unrestricted stock awards	11,655		11,655
Issuance of unrestricted stock awards (in shares)		0
Exercise of options and warrants to purchase common stock	3,289	$ 2	3,287
Exercise of options and warrants to purchase common stock (in shares)		225,767
Issuance of common stock (in shares)		(123,428)			(6,781)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	1	$ 1
Common shares withheld for taxes	(1,904)		(1,904)
Common shares withheld for taxes (in shares)		(46,750)
Stock Issued During Period, Value, New Issues	(280)	$ 0	(280)
Excess tax benefit	1,555		1,555
Issuance of common stock to employees under employee stock purchase plan	208		208
Issuance of common stock to employees under employee stock purchase plan (in shares)		5,087
Net income	71,840			71,840
Balance at Jan. 28, 2017	$ 331,405	$ 549	$ 321,603	$ 9,253
Balance, common stock, shares at Jan. 28, 2017	54,904,954	54,904,954.000
Net Income (Loss) Available to Common Stockholders, Basic	$ 71,840