CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance, value at Jul. 26, 2014	$ 484,934	$ 11,330	$ 131,819	$ (158)	$ 341,943
Beginning balance, shares at Jul. 26, 2014		33,990,589
Increase (Decrease) in Stockholders' Equity
Stock options exercised, value	8,922	$ 245	8,677
Stock options exercised, shares		735,330
Stock-based compensation, value	13,923	$ 1	13,922
Stock-based compensation, shares		4,062
Issuance of restricted stock, net of tax withholdings, value	(4,711)	$ 107	(4,818)
Issuance of restricted stock, net of tax withholdings, shares		321,722
Repurchase of common stock, value	$ (87,146)	$ (556)	(86,590)
Repurchase of common stock, shares	(1,669,924)	(1,669,924)
Tax benefits from stock-based compensation	$ 7,994		7,994
Other comprehensive loss	(1,040)			(1,040)
Net income	84,324				84,324
Ending balance, value at Jul. 25, 2015	507,200	$ 11,127	71,004	(1,198)	426,267
Ending balance, shares at Jul. 25, 2015		33,381,779
Increase (Decrease) in Stockholders' Equity
Stock options exercised, value	2,745	$ 71	2,674
Stock options exercised, shares		212,619
Stock-based compensation, value	16,850	$ 1	16,849
Stock-based compensation, shares		3,015
Issuance of restricted stock, net of tax withholdings, value	(12,604)	$ 111	(12,715)
Issuance of restricted stock, net of tax withholdings, shares		334,475
Repurchase of common stock, value	$ (169,997)	$ (837)	(152,033)		(17,127)
Repurchase of common stock, shares	(2,511,578)	(2,511,578)
Tax benefits from stock-based compensation	$ 13,003		13,003
Equity component of 0.75% convertible senior notes due 2021, net	112,554		112,554
Sale of warrants	74,690		74,690
Purchase of convertible note hedges	(115,818)		(115,818)
Other comprehensive loss	(76)			(76)
Net income	128,740				128,740
Ending balance, value at Jul. 30, 2016	$ 557,287	$ 10,473	10,208	(1,274)	537,880
Ending balance, shares at Jul. 30, 2016	31,420,310	31,420,310
Increase (Decrease) in Stockholders' Equity
Stock options exercised, value	$ 1,449	$ 34	1,415
Stock options exercised, shares		102,831
Stock-based compensation, value	20,805	$ 1	20,804
Stock-based compensation, shares		2,847
Issuance of restricted stock, net of tax withholdings, value	(10,767)	$ 92	(10,859)
Issuance of restricted stock, net of tax withholdings, shares		274,303
Repurchase of common stock, value	$ (62,909)	$ (238)	(19,861)		(42,810)
Repurchase of common stock, shares	(713,006)	(713,006)
Tax benefits from stock-based compensation	$ 8,385		8,385
Other comprehensive loss	116			116
Net income	157,217
Ending balance, value at Jul. 29, 2017	$ 671,583	$ 10,362	10,092	(1,158)	652,287
Ending balance, shares at Jul. 29, 2017	31,087,285	31,087,285
Increase (Decrease) in Stockholders' Equity
Stock options exercised, value	$ 745	$ 18	727
Stock options exercised, shares		52,553
Stock-based compensation, value	13,277	$ 1	13,276
Stock-based compensation, shares		1,492
Issuance of restricted stock, net of tax withholdings, value	(12,581)	$ 81	(7,985)		(4,677)
Issuance of restricted stock, net of tax withholdings, shares		244,339
Repurchase of common stock, value	$ (16,875)	$ (67)	(9,940)		(6,868)
Repurchase of common stock, shares	(200,000)	(200,000)
Other comprehensive loss	$ 12			12
Net income	68,835
Ending balance, value at Jan. 27, 2018	$ 724,996	$ 10,395	$ 6,170	$ (1,146)	$ 709,577
Ending balance, shares at Jan. 27, 2018	31,185,669	31,185,669