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Intangible Assets - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Apr. 30, 2018
Apr. 30, 2017
Apr. 30, 2016
Finite-Lived Intangible Assets [Line Items]      
Amortization expense of intangible assets $ 21.0 $ 20.1 $ 10.7
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