Revenue and Performance Obligations - Schedule of Revenue by Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 427,620	$ 271,653	$ 159,935
Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	100.00%	100.00%	100.00%
Self-managed subscription
Disaggregation of Revenue [Line Items]
Total revenue	$ 299,880	$ 202,419	$ 123,898
Self-managed subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	70.00%	74.00%	77.00%
License - self-managed
Disaggregation of Revenue [Line Items]
Total revenue	$ 53,536	$ 39,474	$ 25,759
License - self-managed | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	12.00%	14.00%	16.00%
Subscription
Disaggregation of Revenue [Line Items]
Total revenue	$ 246,344	$ 162,945	$ 98,139
Subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	58.00%	60.00%	61.00%
SaaS
Disaggregation of Revenue [Line Items]
Total revenue	$ 92,290	$ 45,835	$ 25,484
SaaS | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	22.00%	17.00%	16.00%
Total subscription
Disaggregation of Revenue [Line Items]
Total revenue	$ 392,170	$ 248,254	$ 149,382
Total subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	92.00%	91.00%	93.00%
Professional services
Disaggregation of Revenue [Line Items]
Total revenue	$ 35,450	$ 23,399	$ 10,553
Professional services | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	8.00%	9.00%	7.00%