Revenue Recognition - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021	Apr. 30, 2021
Revenue Recognition [Line Items]
Amounts received for reimbursement of travel and other out-of-pocket expenses	$ 28,000	$ 0	$ 69,000	$ 16,000
Deferred revenue recognized	17,500,000		34,400,000
Total deferred commissions	38,200,000		38,200,000		$ 37,682,000
Impairment losses	0	0	$ 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
Sales Commissions
Revenue Recognition [Line Items]
Total deferred commissions	3,500,000		$ 3,500,000		$ 3,900,000
Amortization of sales commissions	$ 500,000	$ 500,000	$ 1,500,000	$ 1,400,000