Income Taxes - Schedule of Tax Effect of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Deferred tax assets:
Net operating loss ("NOL") carryforwards	$ 23,219	$ 14,410
Operating lease liabilities	1,634	1,183
Other	4,936	2,615
Subtotal	29,789	18,208
Less: valuation allowance	(28,212)	(17,030)
Deferred tax assets, net of valuation allowance	1,577	1,178
Deferred tax liabilities:
Operating lease - Right-of-use assets	(1,570)	(1,158)
Other	$ (7)	$ (20)