BASIS OF PRESENTATION (Details)	3 Months Ended
	Jul. 31, 2018 USD ($) item	Jul. 31, 2017 USD ($)	May 01, 2018 USD ($)	Apr. 30, 2018 USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Number of primary product revenue streams | item	2
Revenue from contracts with performance obligations satisfied over time	90.00%
Assets
Contract assets	$ 233,000		$ 102,000
Equity
Accumulated deficit	(8,684,000)		$ (8,641,000)	$ (8,743,000)
Net sales	4,473,000
Cost of goods sold	2,994,000	$ 3,273,000
Gross profit	1,479,000	1,256,000
Loss from operations	(34,000)	(296,000)
Loss before benefit for income taxes	(58,000)	(307,000)
Benefit for income taxes	(15,000)	(114,000)
Net loss	(43,000)	(193,000)
Net cash provided (used) in operating activities	$ (258,000)	$ 454,000
Aerospace and defense industries
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of revenue	90.00%
Industrial and commercial
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of revenue	7.00%
ASU 2014-09 | Balances Without Adoption of ASC 606
Equity
Net sales	$ 4,232,000
Cost of goods sold	2,884,000
Gross profit	1,348,000
Loss from operations	(165,000)
Loss before benefit for income taxes	(189,000)
Benefit for income taxes	(49,000)
Net loss	(140,000)
Net cash provided (used) in operating activities	(258,000)
ASU 2014-09 | Adjustments
Assets
Contract assets	233,000			102,000
Equity
Accumulated deficit				$ 102,000
Net sales	241,000
Cost of goods sold	110,000
Gross profit	131,000
Loss from operations	131,000
Loss before benefit for income taxes	131,000
Benefit for income taxes	34,000
Net loss	$ 97,000