Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Oct. 31, 2021	Apr. 30, 2021
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 11,595	$ 10,046
Less: Accumulated depreciation	(4,612)	(3,956)
Property and equipment, net	6,983	6,090
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	246	246
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,563	1,461
Capitalized software development costs
Property, Plant and Equipment [Line Items]
Total property and equipment	484	484
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	7,788	6,640
Assets in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	1,402	1,211
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 112	$ 4