BENEFIT PLANS - Maximum number of shares issued to employees that could be vested (Details) - $ / shares	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
BENEFIT PLANS
Number of Shares - Non-vested	32,834	42,667
Number of Shares - Granted	9,000	9,000
Number of Shares - Vested	(12,834)	(14,833)
Number of Shares - Forfeited		(4,000)
Number of Shares - Non-vested	29,000	32,834
Weighted Average Grant Date Fair Value Non-vested	$ 6.86	$ 6.87
Weighted Average Grant Date Fair Value Granted	4.63	6.35
Weighted Average Grant Date Fair Value Vested	6.86	6.59
Weighted Average Grant Date Fair Value Forfeited		6.76
Weighted Average Grant Date Fair Value Non-vested	$ 6.18	$ 6.86