Share-Based Payments (Tables)

9 Months Ended

Jan. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Allocation of Share Based Compensation Expense

Stock-based compensation expense was recognized as follows (table in thousands):

	Three Months Ended January 31,				Nine Months Ended January 31,
	2017		2016		2017		2016
General and administrative	$	184	$	488	$	1,482	$	1,600
Sales and marketing	7		27		194		173
Research and development	44		49		174		262
TOS cost of sales	2		2		49		28
POS cost of sales	—		1		2		27
Total stock-based compensation expense	$	237	$	567	$	1,901	$	2,090

Valuation Assumptions for Stock Options

Black-Scholes assumptions used to calculate the fair value of options granted during the three and nine months ended January 31, 2017 and 2016 were as follows:

	Three Months Ended January 31,		Nine Months Ended January 31,
	2017	2016	2017	2016
Expected term in years	3	2.5 - 6	3 - 6	2.5 - 6
Risk-free interest rates	0.59% - 1.90%	0.995% - 1.75%	0.59% - 1.90%	0.995% - 1.77%
Volatility	72.12% - 87.96%	82.72% - 91.98%	72.12% - 87.96%	82.72% - 92.32%
Dividend yield	—%	—%	—%	—%

Summary of Stock Option Activity

The Company’s stock options activity for the nine months ended January 31, 2017 was as follows:

	Non- Employees		Directors and Employees		Total		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding, May 1, 2016	51,250		2,161,507		2,212,757		$	5.58	6.1	$	10,000
Granted	—		2,420,681		2,420,681		1.99		7.0	6,688,000
Exercised	—		—		—		—
Forfeited	—		(421,487	)	(421,487	)	2.03
Canceled	—		(1,793,779	)	(1,793,779	)	4.92
Expired	(1,250	)	(108,218	)	(109,468	)	7.86
Outstanding, January 31, 2017	50,000		2,258,704		2,308,704		2.76		6.6	$	6,201,000
Vested and expected to vest as of January 31, 2017	50,000		2,258,704		2,308,704		2.76		6.6	$	6,201,000
Exercisable as of January 31, 2017	33,336		1,954,383		1,987,719		2.97		6.0	$	4,672,000

Summary of Warrant Activity

Activity related to these warrants, which expire at various dates through March 2020, is summarized as follows:

	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding, May 1, 2016	2,109,840	$	5.54	3.6	$	—
Granted	—	—		—	—
Exercised	—	—		—	—
Expired	—	—		—	—
Outstanding, January 31, 2017	2,109,840	$	5.54	2.9	$	—