Stockholder's Equity (Details Textuals) - $ / shares	12 Months Ended			70 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2017
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	230,488,296	220,244,120		230,488,296
Common stock, reserved for issuance of stock options	28,878,913	41,625,934		28,878,913
Common stock, shares issued	230,488,296	220,244,120		230,488,296
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
Stock Repurchased and Retired During Period, Shares	0	5,877,038	463,000	106,913,602
Employee Stock Purchase Plan (ESPP)
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, reserved for issuance of stock options	1,788,909	1,979,622		1,788,909