Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2017 Customer	Oct. 31, 2016 Customer	Oct. 31, 2017 Customer	Oct. 31, 2016 Customer	Apr. 30, 2017 USD ($) Customer
Accounting Policies [Abstract]
Number of clients that accounted for more than 10% of account receivables | Customer	0		0		0
Number of clients that accounted for more than 10% of revenue | Customer	0	0	0	0
Adjustments for New Accounting Pronouncement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Tax Assets, Other					$ 12,700
Deferred Tax Assets, Valuation Allowance					12,700
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 326
Minimum [Member] | Software as a Service (“SaaS”)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Service agreement period			1 year
Maximum [Member] | Software as a Service (“SaaS”)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Service agreement period			3 years