Summary of Activity under Share-Based Payment Plans (Detail)	9 Months Ended
Jan. 31, 2019 USD ($) $ / shares shares
Options
Outstanding	676,000
Granted	0
Exercised	0
Forfeited or expired	0
Outstanding	676,000
Exercisable	676,000
Available for grant	507,611
Weighted Average Exercise Price
Outstanding \| $ / shares	$ 1.10
Outstanding \| $ / shares	1.10
Exercisable \| $ / shares	$ 1.10
Weighted Average Remaining Contractual Term (Years)
Outstanding	3 years 6 months
Exercisable	3 years 6 months
Aggregate Intrinsic Value
Outstanding \| $	$ 923,800
Exercisable \| $	$ 923,800

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.