Summary of Significant Accounting Policies - Summary of Potentially Dilutive Stock-based Instruments (Details) - shares	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Class of Stock [Line Items]
Total common stock equivalents	4,322,597	4,113,842
Warrant [Member]
Class of Stock [Line Items]
Total common stock equivalents	2,109,840	2,109,840
Employee Stock Option [Member]
Class of Stock [Line Items]
Total common stock equivalents	2,212,757	2,004,002