Stockholders' Equity (Tables)

6 Months Ended

Oct. 31, 2015

Stockholders Equity Tables

Fair value of stock options granted

	Three months ended October 31, 2015	Six months ended October 31, 2015
Expected term (years)	3.0	2.5-3.0
Expected volatility	80%	79%-80%
Dividend yield	0	0
Risk-free interest rate	1.01%	.90% -1.01%
Weighted average per share grant date fair value	$0.78	$0.78 - $1.03

Summary of option activity

	Shares		Weighted average exercise price		Weighted average remaining contractual life		Aggregate intrinsic value (1)
Balance May 1, 2015		125,746	$	8.48		3.59	$	—
Granted		238,667	$	1.63		6.49	$	—
Expired		36,996	$	12.71		—		—
Balance October 31, 2015		327,414	$	3.01		3.34	$	—
Exercisable October 31, 2015		279,414	$	3.27		3.09	$	—
Expected to vest October 31, 2015		327,414	$	3.01		3.34	$	—

Warrants

	Shares		Weighted average exercise price		Weighted average remaining contractual life years		Aggregate intrinsic value (1)
Balance May 1, 2015		3,308,275	$	3.52		—		—
Issued		50,000	$	2.50		—		—
Balance October 31, 2015		3,358,275	$	3.51		—		—