ACCRUED LIABILITIES (Details) - USD ($)	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
Employee related expenses:
Accrued payroll	$ 286,000	$ 167,000
Accrued payroll taxes	22,000	13,000
Accrued employee benefits	165,000	129,000
Total employee related expenses	473,000	309,000
Other, including interest:
Warranty reserve	22,000	300,000
Property taxes	20,000	18,000
Deferred rent	206,000	129,000
Other	103,000	61,000
Total other	351,000	508,000
Total accrued liabilities	824,000	817,000
Changes in warranty reserve
Balance, May 1	300,000	24,000
Credit memos issued	(212,000)	(52,000)
Provision for warranty accrual	(66,000)	328,000
Balance, April 30	$ 22,000	$ 300,000