Consolidated Statement of Shareholders' Equity - 9 months ended Oct. 28, 2017 - USD ($) $ in Thousands	Total	Common stock [Member]	Additional Paid-in Capital [Member]	Accumulated deficit [Member]
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
Share-based compensation expense	$ 11,785		11,785	0
Issuance of unrestricted stock awards	176	$ 0	176	0
Issuance of unrestricted stock awards (in shares)		3,472
Exercise of options to purchase common stock	$ 3,797	$ 1	3,796	0
Exercise of options to purchase common stock (in shares)	138,312	138,312
Common shares withheld for taxes	$ (1,063)		$ (1,063)
Common shares withheld for taxes (in shares)		(26,117)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	135,000	2,600	135,000
Net income	$ 35,074
Balance at Oct. 28, 2017	$ 381,311	$ 552	$ 336,432	$ 44,327
Balance, common stock, shares at Oct. 28, 2017	55,235,031	55,235,031.000