Accrued Liabilities (Details) (USD $)	Apr. 30, 2012	Apr. 30, 2011
Payables and Accruals [Line Items]
Accrued Payroll, Current	$ 111,000	$ 110,000
Accrued Payroll Taxes, Current	42,000	40,000
Accrued Employee Benefits, Current	43,000	28,000
Employee-related Liabilities, Current	196,000	178,000
Product Warranty Accrual	20,000	36,000
Property Tax Accrual, Current	12,000	24,000
Deferred Compensation Liability, Current	52,000	80,000
Other Accrued Liabilities, Current	1,000	18,000
Total Other Accrued Liabilities	85,000	158,000
Accounts Payable and Accrued Liabilities, Current	$ 281,000	$ 336,000