Summary of Significant Accounting Policies - Calculations of Earnings Per Share (Details) - USD ($)	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Basic and diluted net loss per share computation
Net loss attributable to common stockholders	$ (6,883,882)	$ (10,445,537)
Weighted Average common shares (in shares)	10,684,395	8,695,199
Basic and diluted net loss per share (in dollars per share)	$ (0.64)	$ (1.20)