Share-Based Payments (Tables)

9 Months Ended

Jan. 31, 2018

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,
	2018		2017		2018		2017
General and administrative	$	110	$	184	$	629	$	1,482
Sales and marketing	7		7		47		194
Research and development	33		44		156		174
TOS cost of sales	2		2		30		49
POS cost of sales	—		—		1		2
Total stock-based compensation expense	$	152	$	237	$	863	$	1,901

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, 2018 and 2017 were as follows:

	Three Months Ended January 31,		Nine Months Ended January 31,
	2018	2017	2018	2017
Expected term in years	3	3	3 - 6	3 - 6
Risk-free interest rates	1.98%	0.59% - 1.90%	1.77% - 1.98%	0.59% - 1.90%
Volatility	85.59%	72.12% - 87.96%	85.59% - 87.66%	72.12% - 87.96%
Dividend yield	—%	—%	—%	—%

Summary of Stock Option Activity

The Company’s stock options activity for the nine months ended January 31, 2018 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, 2017	50,000	2,258,704		2,308,704		$	2.86	6.1	$	1,282,000
Granted	—	267,310		267,310		2.68
Exercised	—	(12,500	)	(12,500	)	3.00
Forfeited	—	(6,042	)	(6,042	)	7.58
Canceled	—	—		—		—
Expired	—	(38,627	)	(38,627	)	5.21
Outstanding, January 31, 2018	50,000	2,468,845		2,518,845		2.80		5.8	$	3,921,000
Vested and expected to vest as of January 31, 2018	50,000	2,468,845		2,518,845		2.80		5.8	$	3,921,000
Exercisable as of January 31, 2018	25,836	2,389,471		2,415,307		2.77		5.7	$	3,847,000

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, 2017	2,004,284	$	5.57	2.8	$	—
Granted	—	—		—	—
Exercised	—	—		—	—
Expired	—	—		—	—
Outstanding, January 31, 2018	2,004,284	$	5.57	2.3	$	—