Organization, Use of Estimates and Basis of Presentation - Calculation of Earnings Per Share (Details) - USD ($)	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Basic loss per share computation
Net loss attributable to common stockholders	$ (2,546,449)	$ (2,913,101)
Weighted average common shares outstanding, basic and diluted (in shares)	9,835,279	8,702,237
Basic and diluted net loss per share (in dollars per share)	$ (0.26)	$ (0.33)