Share-Based Payments (Details Textual) (USD $)	3 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Apr. 30, 2014
Stock-based compensation expense	$ 808,000	$ 552,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	215,000
Share Based Compensation Arrangement By Share Based Payment Award Warrants Outstanding	3,276,667		3,276,667
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 0.69	$ 0.40
Warrants Not Settleable in Cash, Fair Value Disclosure	1,860,000		2,010,000
Percentage Of Cash Penalties	1.00%
Purchase Price Limit Percentage	10.00%
Minimum [Member]
Potential Penalties Amount	50,000
Maximum [Member]
Potential Penalties Amount	130,000
Chief Executive Officer and President [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	3,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures, Total	3,000,000
April 2011 Private Placement [Member]
Warrants Issued During Period for Common Stock	1,266,667
April 2011 Private Placement [Member] | Minimum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.50
April 2011 Private Placement [Member] | Maximum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.90
January 2013 Private Placement [Member]
Warrants Issued During Period for Common Stock	1,860,000
Warrants and Rights Outstanding	$ 800,000
Equity Instrument [Member]
Warrants Issued During Period for Common Stock	150,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 1.00