FINANCING AGREEMENTS (Details)	9 Months Ended
	Jan. 31, 2018 USD ($) agreement	Apr. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Feb. 21, 2014 USD ($)
Long-term indebtedness
Total long-term debt	$ 1,898,000	$ 1,048,000
Less current installments	1,736,000	603,000
Long-term debt, excluding current installments	$ 162,000	445,000
Mortgage note payable
Long-term indebtedness
Annual prepayment limit				$ 100,000
Line of Credit
Long-term indebtedness
Number of agreements | agreement	2
Capital Leases
Long-term indebtedness
Total long-term debt	$ 199,000
Note payable 4.05 percent | Mortgage note payable
Long-term indebtedness
Total long-term debt	$ 384,000	415,000
Rate	4.05%
Monthly installments	$ 4,873
Final payment	349,000
Working line of credit 4.00 percent | Line of Credit
Long-term indebtedness
Total long-term debt	750,000	465,000
Maximum borrowing	$ 1,250,000
Working line of credit 4.00 percent | Line of Credit | Minimum
Long-term indebtedness
Rate	4.00%
Working line of credit 4.00 percent | Line of Credit | Prime Rate
Long-term indebtedness
Rate	4.25%
Building line of credit 4.00 percent | Line of Credit
Long-term indebtedness
Total long-term debt	$ 465,000
Maximum borrowing			$ 500,000
Building line of credit 4.00 percent | Line of Credit | Minimum
Long-term indebtedness
Rate			4.00%
Building line of credit 4.00 percent | Line of Credit | Prime Rate
Long-term indebtedness
Rate			4.25%
Note payable 4.75 percent | Note Payable
Long-term indebtedness
Total long-term debt	$ 6,000	28,000
Rate	4.75%
Monthly installments	$ 2,269
Note payable 3.75 percent | Note Payable
Long-term indebtedness
Total long-term debt	9,000	25,000
Notes Payable	$ 0
Rate	3.75%
Monthly installments	$ 2,112
Note payable 4.05 percent | Note Payable
Long-term indebtedness
Total long-term debt	$ 85,000	$ 115,000
Rate	4.05%
Monthly installments	$ 3,680
Equipment line of credit
Long-term indebtedness
Equipment financing maximum borrowing	$ 500,000