Income Taxes - Tax Effects of Temporary Differences That Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Deferred tax assets:
Accruals and expenses not deducted for tax purposes	$ 473	$ 565
State net operating loss carryforwards	49	136
Fixed asset basis differences	823	797
Nonqualified stock options	1,740	1,184
Foreign net operating loss carryforwards	3,873	3,141
Right of use liability	251	390
Tax credit carryforwards	83	83
Total gross deferred tax assets	7,292	6,296
Less valuation allowance	(3,891)	(3,252)
Net deferred tax	3,401	3,044
Deferred tax liabilities:
Capitalized computer software development costs	(396)	(1,192)
Net gains/losses on trading securities	(1,993)	(1,891)
Goodwill and intangible assets basis differences	(1,399)	(1,003)
Right of use asset	(234)	(364)
Deferred agent commissions	(1,151)	(1,221)
Total gross deferred tax liabilities	(5,173)	(5,671)
Net deferred tax liabilities	$ (1,772)	$ (2,627)