Stock Appreciation Rights (Details) (Stock Appreciation Rights (SARs) [Member], USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
SARS Valuation Assumptions [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	320,000	280,000	320,000	280,000
Stock Appreciation Rights, Weighted Average Grant Price	$ 0.409	$ 0.421	$ 0.409	$ 0.421
Stock Appreciation Rights, Weighted Average Contractual Life Remaining	5.10	5.53	5.10	5.53
Stock Appreciation Rights, Weighted Average Market Price			$ 0.530	$ 0.400
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate			148.76%	132.96%
Weighted Average Expected Life	4.60	5.11	4.60	5.11
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate			0.80%	0.89%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate			0.00%	0.00%
Stock Appreciation Rights, Weighted Average Fair Value Price			$ 0.498	$ 0.374
Weighted Average Aggregate Fair Value			$ 110,000	$ 75,000
Weighted Average Aggregate Intrinsic Value			33,000	19,000
Stock Appreciation Rights, Compensation Expense	63,000	(6,000)	72,000	(5,000)
Unrecognized Compensation Expense Related to Non-Vested SARS Granted			24,000	17,000
Expected Period to Recognize Compensation Expense Related to Non-Vested SARSs Granted	1.87	2.00	1.87	2.00
Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent	$ 124,000	$ 75,000	$ 124,000	$ 75,000
Maximum [Member]
SARS Valuation Assumptions [Line Items]
Stock Appreciation Rights, Upper Range of Grant Price	$ 0.695	$ 0.695	$ 0.695	$ 0.695
Minimum [Member]
SARS Valuation Assumptions [Line Items]
Stock Appreciation Rights, Lower Range of Grant Price	$ 0.208	$ 0.208	$ 0.208	$ 0.208