Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 5.6	$ 2.8	$ 8.3	$ 5.1
Weighted-average period for amortization of intangible assets			5 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-average period for amortization of intangible assets			5 years
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted-average period for amortization of intangible assets			6 years
Patents, trademarks, and trade names
Finite-Lived Intangible Assets [Line Items]
Weighted-average period for amortization of intangible assets			5 years