Income Taxes - Schedule of Significant Items Comprising the Company's Deferred Taxes (Details) - USD ($)	Apr. 30, 2022	Apr. 30, 2021
Deferred tax assets:
Accrued expense	$ 1,114,000	$ 144,000
Deferred rent	0	58,000
Foreign tax credit	0	0
Net operating losses	125,000	19,000
Research and development credits	5,299,000	4,011,000
Stock compensation	868,000	0
Lease liability	3,900,000	0
Others	3,000	0
Total deferred tax assets	11,309,000	4,232,000
Deferred tax liabilities
Property and equipment basis	(1,162,000)	(900,000)
Right of use assets	(3,842,000)	0
Others	0	(16,000)
Total deferred tax liabilities	(5,004,000)	(916,000)
Valuation allowance	(5,170,000)	(3,706,000)
Net deferred taxes	$ 1,135,000
Net deferred taxes		$ (390,000)