Stockholder's Equity (Details Textuals) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			12 Months Ended			68 Months Ended
	Oct. 31, 2019	Apr. 30, 2019	Jan. 31, 2018	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for Employee Stock-Based Tax Withholdings	$ 101,348	$ 45,565	$ 0	$ 103,451	$ 46,888	$ 1,115
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares authorized				400,000,000	400,000,000		400,000,000
Common stock par value (in dollars per share)				$ 0.0001	$ 0.0001		$ 0.0001
Common stock, shares outstanding				235,315,337	229,790,268		235,315,337
Common stock, reserved for issuance of stock options				12,977,173	20,502,335		12,977,173
Common stock, shares issued				235,315,337	229,790,268		235,315,337
Preferred stock, shares authorized				5,000,000	5,000,000		5,000,000
Preferred stock par value (in dollars per share)				$ 0.0001	$ 0.0001		$ 0.0001
Preferred stock, shares issued				0	0		0
Preferred stock, shares outstanding				0	0		0
Employee Stock Purchase Plan
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, reserved for issuance of stock options				1,303,592	1,426,698		1,303,592
Stock Repurchase Program 2011 [Member]
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock Repurchased and Retired During Period, Shares					7,635,596		114,549,198
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased				81,450,802			81,450,802
Settlement with Taxing Authority [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for Employee Stock-Based Tax Withholdings				$ 101,300	$ 45,600	$ 0