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. 25, 2015	$ 507,200	$ 11,127	$ 71,004	$ (1,198)	$ 426,267
Beginning 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
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				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
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)
Tax benefits from stock-based compensation	$ 7,800
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
Increase (Decrease) in Stockholders' Equity
Stock options exercised, value	$ 871	$ 27	844
Stock options exercised, shares		82,235
Stock-based compensation, value	20,187	$ 1	20,186
Stock-based compensation, shares		3,122
Issuance of restricted stock, net of tax withholdings, value	(4,657)	$ 54	(4,711)
Issuance of restricted stock, net of tax withholdings, shares		159,005
Tax benefits from stock-based compensation	200
Other comprehensive loss	(136)			(136)
Net income	62,907
Ending balance, value at Jan. 26, 2019	$ 804,168	$ 10,477	$ 22,489	$ (1,282)	$ 772,484
Ending balance, shares at Jan. 26, 2019	31,430,031	31,430,031