Revenue Recognition - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019	Apr. 30, 2019
Revenue Recognition [Line Items]
Expense reimbursement included in professional services	$ 30,600,000	$ 27,003,000	$ 86,193,000	$ 82,435,000
Deferred revenue recognized	14,000,000		29,000,000
Transaction price allocated to remaining performance obligations	80,000,000		80,000,000
Total deferred commissions	34,419,000		34,419,000		$ 33,283,000
Impairment losses	0		$ 0
Minimum
Revenue Recognition [Line Items]
Contractual period of maintenance contract			1 year
Maximum
Revenue Recognition [Line Items]
Contractual period of maintenance contract			3 years
Reimbursement
Revenue Recognition [Line Items]
Expense reimbursement included in professional services	400,000	$ 300,000	$ 1,300,000	$ 1,100,000
Sales Commissions
Revenue Recognition [Line Items]
Total deferred commissions	3,500,000		3,500,000		$ 2,300,000
Amortization of sales commissions	$ 600,000		$ 1,400,000