Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2023	Apr. 30, 2022
Deferred tax assets
Accrued payroll	$ 3,971	$ 521
Other accruals & reserves	5,815	6,185
Operating lease liability	8,868	6,957
Deferred revenue	2,221	442
Depreciation	0	2,099
Net operating losses	116,111	114,291
R&D tax credit	10,302	6,618
Stock based compensation	10,595	15,669
Capitalized R&D expenditure	30,696	0
Other	457	905
Gross deferred tax assets	189,036	153,687
Valuation allowance	(180,571)	(144,678)
Total deferred tax assets	8,465	9,009
Deferred tax liabilities
Prepaid expenses	(1,956)	(2,384)
Depreciation	(2,580)	0
Operating lease right-of-use assets	(3,929)	(6,625)
Total deferred tax liabilities	(8,465)	(9,009)
Net deferred tax assets (liabilities)	$ 0	$ 0