Changes in value of derivative warrant liability - Derivative Liabilities (Details) - USD ($)	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Balance - Derivative warrant liability Value	$ 2,048,846	$ 2,363,415
No. of Warrants - Derivative warrant liability	383,877,521	512,911,037
Forfeited or expired, Value	$ (455,573)
Forfeited or expired, No. of Warrants	(129,033,516)
Increase (Decrease) in fair value of derivative warrant liability	$ 141,004	$ (2,737,840)
July 2014
Balance - Derivative warrant liability Value	$ 2,635,643
No. of Warrants - Derivative warrant liability	239,788,852
Price Protection
Additional warrants issued	$ 2,111,077
June 2015
Additional warrants issued	354,535
January 2014
Additional warrants issued	942,279
March 2014
Additional warrants issued	$ 2,016,064