Share-Based Payments (Tables)

6 Months Ended

Oct. 31, 2019

Share-based Payment Arrangement [Abstract]

Allocation of Share Based Compensation Expense

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

	Three Months Ended October 31,				Six Months Ended October 31,
	2019		2018		2019			2018
General and administrative	$	39	$	23	$	171		$	83
Sales and marketing	27		40		49			47
Research and development	2		5		5			9
Cost of oncology services	9		20		(17		)	32
Total stock-based compensation expense	$	77	$	88	$	208		$	171

Valuation Assumptions for Stock Options

Black-Scholes assumptions used to calculate the fair value of options granted during the three and six months ended October 31, 2019 and 2018 were as follows:

	Three Months Ended October 31,		Six Months Ended October 31,
	2019	2018	2019	2018
Expected term in years	6	6	6	6
Risk-free interest rates	1.57%	2.78%	1.57	2.78%-2.82%
Volatility	71.11%	83.88%	71.11%	83.88%-84.35%
Dividend yield	—%	—%	—%	—%

Summary of Stock Option Activity

The Company’s stock options activity for the six months ended October 31, 2019 was as follows:

	Directors and Employees		Non- Employees		Total		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding, May 1, 2019	2,373,626		50,000		2,423,626		$	3.19	5.3	$	14,557,000
Granted	154,000		—		154,000		5.23
Exercised	(625	)	—		(625	)	5.81
Forfeited	(41,875	)	—		(41,875	)	7.99
Canceled	(4,583	)	—		(4,583	)	11.90
Expired	(70,001	)	(6,668	)	(76,669	)	8.04
Outstanding, October 31, 2019	2,410,542		43,332		2,453,874		3.07		5.1	$	6,216,000
Vested and expected to vest as of October 31, 2019	2,410,542		43,332		2,453,874		3.07		5.1	$	6,216,000
Exercisable as of October 31, 2019	2,068,437		17,501		2,085,938		2.64		4.4	$	6,004,000

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, 2019	1,671,440		$	6.20	0.9	$	5,730,000
Granted	—		—		—	—
Exercised	—		—		—	—
Canceled	—		—		—	—
Expired	(1,667	)	4.80		—	—
Outstanding, October 31, 2019	1,669,773		$	5.66	0.4	$	76,000