Revenue - Disaggregated Revenue by Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 183,217	$ 156,666	$ 91,605
North America
Disaggregation of Revenue [Line Items]
Total revenue	119,795	121,485	61,314
Europe, the Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	56,030	33,086	27,629
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	5,992	2,095	2,662
Rest of World
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,400	$ 0	$ 0
United States \| Revenue \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Geographic concentration risk, percentage	65.00%	78.00%	66.00%
France \| Revenue \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Geographic concentration risk, percentage	12.00%	10.50%	15.00%
Netherlands \| Revenue \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Geographic concentration risk, percentage	12.00%

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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