Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended	12 Months Ended
	Oct. 04, 2018 USD ($)	Oct. 31, 2018 USD ($)	Apr. 30, 2020 USD ($) segment Customer	Apr. 30, 2019 USD ($) Customer	Apr. 30, 2018 USD ($) Customer	May 01, 2019 USD ($)	Apr. 30, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Re-measurement gain (loss) recognized			$ (2,200,000)	$ (200,000)	$ (1,300,000)
Allowance for doubtful accounts			1,247,000	1,411,000	776,000		$ 357,000
Unbilled accounts receivable			$ 2,622,000	1,710,000	1,139,000		$ 1,114,000
Number of operating segments | segment			1
Number of reportable segments | segment			1
Impairment of goodwill			$ 0	0	0
Deferred offering costs		$ 200,000
Additional offering costs		$ 5,500,000
Estimated amortization period of sales commissions			5 years
Advertising costs			$ 7,700,000	6,500,000	1,700,000
Stock-based compensation expense			60,007,000	39,942,000	$ 12,742,000
Customer deposits included in accrued expenses and other liabilities			2,600,000
Customer deposits included in other liabilities, non-current			8,500,000
Operating lease right-of-use assets			32,783,000			$ 28,100,000
Operating lease deferred rents				$ 1,000,000.0
Prepaid rent						200,000
Operating lease liabilities			$ 35,466,000			$ 28,900,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of likelihood that a tax benefit will be sustained			50.00%
Redeemable convertible preference shares
Summary Of Significant Accounting Policies [Line Items]
Terms of conversion			one-to-one
RSAs
Summary Of Significant Accounting Policies [Line Items]
Stock-based compensation expense	$ 1,700,000		$ 200,000
Customer Concentration Risk | Net Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			1
Concentration risk percentage			11.00%
Customer Concentration Risk | Revenue
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			0	0	0
Concentration risk percentage			10.00%	10.00%	10.00%