Balance Sheet Components - Schedule of Cost and Accumulated Depreciation of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 20,825	$ 15,906
Less: accumulated depreciation	(13,065)	(10,458)
Property and equipment, net	$ 7,760	5,448
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives, description	Lesser of estimated useful life or remaining lease term
Total property and equipment	$ 8,405	6,176
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Total property and equipment	$ 5,687	5,393
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 5,072	3,094
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	5 years
Assets under construction
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,661	$ 1,243