Balance Sheet Components - Schedule of Cost and Accumulated Depreciation of Property and Equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2020	Apr. 30, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 20,905	$ 20,825
Less: accumulated depreciation	(12,901)	(13,065)
Property and equipment, net	8,004	7,760
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,070	8,405
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Total property and equipment	$ 5,832	5,687
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 5,151	5,072
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	$ 1,852	$ 1,661