Revenue and Remaining Performance Obligations - Schedule of Revenue by Category (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Disaggregation of Revenue [Line Items]
Amount	$ 144,894	$ 101,106	$ 273,764	$ 190,816
Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	100.00%	100.00%	100.00%	100.00%
Self-managed subscription
Disaggregation of Revenue [Line Items]
Amount	$ 96,781	$ 71,030	$ 185,496	$ 135,842
Self-managed subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	67.00%	71.00%	67.00%	71.00%
License
Disaggregation of Revenue [Line Items]
Amount	$ 15,514	$ 12,272	$ 30,393	$ 22,179
License | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	11.00%	12.00%	11.00%	11.00%
Subscription
Disaggregation of Revenue [Line Items]
Amount	$ 81,267	$ 58,758	$ 155,103	$ 113,663
Subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	56.00%	59.00%	56.00%	60.00%
SaaS
Disaggregation of Revenue [Line Items]
Amount	$ 37,428	$ 20,649	$ 70,055	$ 38,227
SaaS | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	26.00%	20.00%	26.00%	20.00%
Total subscription
Disaggregation of Revenue [Line Items]
Amount	$ 134,209	$ 91,679	$ 255,551	$ 174,069
Total subscription | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	93.00%	91.00%	93.00%	91.00%
Professional services
Disaggregation of Revenue [Line Items]
Amount	$ 10,685	$ 9,427	$ 18,213	$ 16,747
Professional services | Revenue | Product
Disaggregation of Revenue [Line Items]
% of Total Revenue	7.00%	9.00%	7.00%	9.00%