CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
CONSOLIDATED STATEMENTS OF OPERATIONS
Net sales	$ 6,792,000	$ 4,874,000	$ 13,138,000	$ 9,347,000
Cost of goods sold	4,113,000	3,200,000	8,066,000	6,194,000
Gross profit	2,679,000	1,674,000	5,072,000	3,153,000
Operating expenses:
Engineering	394,000	313,000	782,000	615,000
Selling, general and administrative	1,881,000	1,290,000	3,304,000	2,501,000
Operating expenses	2,275,000	1,603,000	4,086,000	3,116,000
Income from operations	404,000	71,000	986,000	37,000
Other expense:
Interest expense, net	23,000	24,000	50,000	48,000
Income (loss) before income tax expense	381,000	47,000	936,000	(11,000)
Income tax expense	75,000	15,000	186,000
Net income (loss)	$ 306,000	$ 32,000	$ 750,000	$ (11,000)
Basic earnings (loss) per share	$ 0.05	$ 0.01	$ 0.13	$ 0.00