Stock-based Payments - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance (in shares)	1,658,239	1,653,646
Granted (in shares)	186,720	166,052
Exercised (in shares)	(36,209)	(108,375)
Canceled (in shares)	(13,874)	(11,209)
Forfeited (in shares)	(14,625)	(36,875)
Expired (in shares)	(4,584)	(5,000)
Outstanding, Ending Balance (in shares)	1,775,667	1,658,239	1,653,646
Vested and expected to vest (in shares)	1,775,667	1,658,239
Exercisable (in shares)	1,438,807	1,354,479
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Outstanding, Beginning Balance (in usd per share)	$ 4.51	$ 3.96
Weighted Average Exercise Price, Granted (in usd per share)	7.22	9.44
Weighted Average Exercise Price, Exercised (in usd per share)	3.21	2.29
Weighted Average Exercise Price, Canceled (in usd per share)	3.93	4.71
Weighted Average Exercise Price, Forfeited (in usd per share)	7.94	7.45
Weighted Average Exercise Price, Expired (in usd per share)	5.40	9.60
Weighted Average Exercise Price, Outstanding, Ending Balance (in usd per share)	4.80	4.51	$ 3.96
Weighted Average Exercise Price, Vested and Expected to Vest (in usd per share)	4.80	4.51
Weighted Average Exercise Price, Exercisable (in usd per share)	$ 4.35	$ 3.93
Weighted Average Remaining Contractual Term, Outstanding, Beginning Balance (in years)		4 years 10 months 24 days	5 years 4 months 24 days
Weighted Average Remaining Contractual Life, Granted	9 years 4 months 24 days	9 years 3 months 18 days
Weighted Average Remaining Contractual Term, Outstanding, Ending Balance (in years)	4 years 7 months 6 days	4 years 10 months 24 days
Weighted Average Remaining Contractual Life (Years), Vested and expected to vest	4 years 7 months 6 days	4 years 10 months 24 days
Weighted Average Remaining Contractual Life (Years), Exercisable	3 years 9 months 18 days	4 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding, Beginning Balance	$ 6,131	$ 11,384
Aggregate Intrinsic Value, Granted	0	0
Aggregate Intrinsic Value, Outstanding, Ending Balance	2,683	6,131	$ 11,384
Aggregate Intrinsic Value, Vested and expected to vest	2,683	6,131
Aggregate Intrinsic Value, Exercisable	$ 2,681	$ 5,778
Directors and Employees
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance (in shares)	1,617,324	1,618,231
Granted (in shares)	186,720	155,552
Exercised (in shares)	(36,209)	(108,375)
Canceled (in shares)	(13,874)	(11,209)
Forfeited (in shares)	(14,625)	(36,875)
Expired (in shares)	0	0
Outstanding, Ending Balance (in shares)	1,739,336	1,617,324	1,618,231
Vested and expected to vest (in shares)	1,739,336	1,617,324
Exercisable (in shares)	1,436,932	1,349,895
Non- Employees
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance (in shares)	40,915	35,415
Granted (in shares)	0	10,500
Exercised (in shares)	0	0
Canceled (in shares)	0	0
Forfeited (in shares)	0	0
Expired (in shares)	(4,584)	(5,000)
Outstanding, Ending Balance (in shares)	36,331	40,915	35,415
Vested and expected to vest (in shares)	36,331	40,915
Exercisable (in shares)	1,875	4,584