Accrued Liabilities - Accrued liabilities (Details) - USD ($)	Apr. 30, 2016	Apr. 30, 2015
Payables and Accruals [Abstract]
Payroll, including vacation	$ 17,000	$ 27,000
Commissions	25,000	10,000
Deferred gain on equipment sale	72,000	72,000
Accounting and audit	25,000	53,000
Other	20,000	120,000
Total accrued liabilities	$ 159,000	$ 282,000