Intangible Assets and Goodwill - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Jul. 31, 2017
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite lived intangible assets	$ 7,600		$ 7,600
Amortization expense related to acquired intangible assets	1,300	$ 2,000
Goodwill	$ 2,344		$ 2,344
Minimum
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, estimated useful lives	1 year
Maximum
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, estimated useful lives	14 years