Organization, Use of Estimates and Basis of Presentation (Tables)

9 Months Ended

12 Months Ended

Jan. 31, 2016

Apr. 30, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended January 31,						Nine Months Ended January 31,
	2016			2015			2016			2015
Basic loss per share computation
Net loss attributable to common stockholders	$	(2,412,381	)	$	(2,816,465	)	$	(7,872,115	)	$	(9,462,281	)
Weighted Average common shares – basic		8,702,237			5,574,447			8,702,237			5,574,244
Basic net loss per share	$	(0.28	)	$	(0.51	)	$	(0.90	)	$	(1.70	)
Diluted loss per share computation
Net loss attributable to common stockholders	$	(2,412,381	)	$	(2,816,465	)	$	(7,872,115	)	$	(9,462,281	)
Less: Gain on derivative warrant liability		—			620,687			—			1,401,314
Loss available to common stockholders	$	(2,412,381	)	$	(3,437,152	)	$	(7,872,115	)	$	(10,863,595	)
Weighted Average common shares		8,702,237			5,574,447			8,702,237			5,574,244
Incremental shares from assumed exercise of warrants and stock options		—			29,351			—			29,351
Adjusted weighted average share – diluted		8,702,237			5,603,798			8,702,237			5,603,595
Diluted net loss per share	$	(0.28	)	$	(0.61	)	$	(0.90	)	$	(1.94	)

	Year Ended April 30,
	2015		2014
Basic loss per share computation
Net loss attributable to common stockholders	$	(13,139,820)	$	(7,406,367)
Weighted Average common shares – basic		5,985,346		5,571,993
Basic net loss per share	$	(2.20)	$	(1.33)
Diluted loss per share computation
Net loss attributable to common stockholders	$	(13,139,820)	$	(7,406,367)
Less: Gain on derivative warrant liability		980,519		—
Loss available to common stockholders	$	(14,120,339)	$	(7,406,367)
Weighted Average common shares		5,985,346		5,571,993
Incremental shares from assumed exercise of warrants and stock options		439,065		—
Adjusted weighted average share – diluted		6,424,410		5,571,993
Diluted net loss per share	$	(2.20)	$	(1.33)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

The following table reflects the total potential share-based instruments outstanding at January 31, 2016 and 2015 that could have an effect on the future computation of dilution per common share:

	January 31,
	2016		2015
Stock options		2,212,571		1,999,167
Warrants		2,109,840		260,556
Total common stock equivalents		4,322,411		2,259,723

The following table reflects the total potential share-based instruments outstanding at April 30, 2015 and 2014 that could have an effect on the future computation of dilution per common share:

	Year Ended April 30,
	2015		2014
Stock options		2,004,002		1,945,920
Warrants		2,109,840		273,056
Total common stock equivalents		4,113,842		2,218,975