Commitments and Contingencies (Details) - USD ($)	12 Months Ended
Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Eligible employee contribution amount (up to)	$ 19,500
Employer profit sharing contribution to 401(k) plan	$ 451,000	$ 429,000	$ 330,000

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration