CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS
Net sales	$ 4,750,000	$ 4,529,000	$ 14,097,000	$ 13,742,000
Cost of goods sold	3,680,000	3,091,000	9,874,000	9,686,000
Gross profit	1,070,000	1,438,000	4,223,000	4,056,000
Operating expenses:
Engineering	351,000	267,000	966,000	806,000
Selling, general and administrative	1,089,000	1,140,000	3,590,000	3,783,000
Operating expenses	1,440,000	1,407,000	4,556,000	4,589,000
Income (loss) from operations	(370,000)	31,000	(333,000)	(533,000)
Other expense:
Interest expense, net	36,000	28,000	84,000	53,000
Income (loss) before income tax expense (benefit)	(406,000)	3,000	(417,000)	(586,000)
Income tax expense		310,000		85,000
Net loss attributable to common shareholders	$ (406,000)	$ (307,000)	$ (417,000)	$ (671,000)
Basic loss per share	$ (0.08)	$ (0.06)	$ (0.08)	$ (0.13)