Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Apr. 30, 2021	Apr. 30, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 10,046	$ 6,765
Less: Accumulated depreciation and amortization	(3,956)	(2,772)
Property and equipment, net	6,090	3,993
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	246	180
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,461	1,209
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	6,640	4,818
Capitalized software development costs
Property, Plant and Equipment [Line Items]
Total property and equipment	484	0
Assets in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	1,211	554
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 4	$ 4