Summary of Estimated Fair Values of Separately Identifiable Assets Acquired and Liabilities Assumed (Detail) (USD $)	Oct. 31, 2014	Jul. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 57,589,000	$ 56,955,000
Pathfinder Therapeutics Inc
Business Acquisition [Line Items]
Inventory and receivables	100,000
Goodwill	600,000
Intangible assets	1,000,000
Total assets acquired	1,700,000
Accrued liabilities	(100,000)
Total liabilities assumed	(100,000)
Total purchase price	1,600,000
Pathfinder Therapeutics Inc | Developed technologies
Business Acquisition [Line Items]
Intangible assets	700,000
Pathfinder Therapeutics Inc | Customer relationships
Business Acquisition [Line Items]
Intangible assets	200,000
Pathfinder Therapeutics Inc | Tradenames
Business Acquisition [Line Items]
Intangible assets	$ 100,000