Summary of Estimated Fair Values of Separately Identifiable Assets Acquired and Liabilities Assumed (Parenthetical) (Detail)	12 Months Ended
	Jul. 31, 2015
Developed technologies
Business Acquisition [Line Items]
Weighted average useful life	10 years
Pathfinder Therapeutics Inc | Developed technologies
Business Acquisition [Line Items]
Weighted average useful life	10 years
Pathfinder Therapeutics Inc | Customer relationships
Business Acquisition [Line Items]
Weighted average useful life	2 years
Pathfinder Therapeutics Inc | Trade names
Business Acquisition [Line Items]
Weighted average useful life	5 years