Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings (Accumulated Deficit) [Member]	Treasury Stock [Member]
Balances at Feb. 01, 2014	$ 545,272	$ 4	$ 584,641	$ 629	$ (37,292)	$ (2,710)
Balances, shares at Feb. 01, 2014		39,124,764				40,353
Stock-based compensation	17,072		17,072
Issuance of restricted stock	0	$ 0	0	0	0	$ 0
Issuance of restricted stock, Shares		7,592
Vested and delivered restricted stock units	(2,795)		(2,795)
Vested and delivered restricted stock units, Shares		56,003
Exercise of stock options—including tax benefit	32,500		32,500
Exercise of stock options-including tax benefit, Shares		956,091
Repurchases of common stock	$ (16,575)					$ (16,575)
Repurchases of common stock, Shares	(251,910)	(251,910)				251,910
Equity component value of convertible note issuance-net	$ 70,506		70,506
Sale of common stock warrant	40,390		40,390
Purchase of convertible note hedge	(73,325)		(73,325)
Net income	91,002				91,002
Net gains (losses) from foreign currency translation	(1,143)			(1,143)
Net unrealized holding gains (losses) on investments	12			12
Balances at Jan. 31, 2015	702,916	$ 4	668,989	(502)	53,710	$ (19,285)
Balances, shares at Jan. 31, 2015		39,892,540				292,263
Stock-based compensation	24,223		24,223
Issuance of restricted stock	0	$ 0	0	0	0	$ 0
Issuance of restricted stock, Shares		6,535
Vested and delivered restricted stock units	(4,863)		(4,863)
Vested and delivered restricted stock units, Shares		78,769
Exercise of stock options—including tax benefit	35,885		35,885
Exercise of stock options-including tax benefit, Shares		608,056
Repurchases of common stock	$ (238)					$ (238)
Repurchases of common stock, Shares	(2,625)	(2,625)				2,625
Equity component value of convertible note issuance-net	$ 77,192		77,192
Sale of common stock warrant	30,390		30,390
Purchase of convertible note hedge	(68,250)		(68,250)
Net income	91,103				91,103
Net gains (losses) from foreign currency translation	(2,164)			(2,164)
Net unrealized holding gains (losses) on investments	(34)			(34)
Balances at Jan. 30, 2016	886,160	$ 4	763,566	(2,700)	144,813	$ (19,523)
Balances, shares at Jan. 30, 2016		40,583,275				294,888
Stock-based compensation	28,930		28,930
Issuance of restricted stock	0	$ 0	0	0	0	$ 0
Issuance of restricted stock, Shares		33,555
Vested and delivered restricted stock units	(1,531)		(1,531)
Vested and delivered restricted stock units, Shares		88,538
Exercise of stock options—including tax benefit	$ (99)		(99)
Exercise of stock options-including tax benefit, Shares		123,265
Repurchases of common stock, Shares	0
Net income	$ 5,401				5,401
Net gains (losses) from foreign currency translation	1,003			1,003
Net unrealized holding gains (losses) on investments	5			5
Balances at Jan. 28, 2017	$ 919,869	$ 4	$ 790,866	$ (1,692)	$ 150,214	$ (19,523)
Balances, shares at Jan. 28, 2017		40,828,633				294,888