Share-Based Payments (Tables)

6 Months Ended

Oct. 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 October 31,				Six Months Ended October 31,
	2018		2017		2018		2017
General and administrative	$	23	$	96	$	83	$	549
Sales and marketing	40		7		47		41
Research and development	5		42		9		122
Cost of oncology solutions	20		3		32		29
Total stock-based compensation expense	$	88	$	148	$	171	$	741

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, 2018 and 2017 were as follows:

	Three Months Ended October 31,		Six Months Ended October 31,
	2018	2017	2018	2017
Expected term in years	6	—	6	6
Risk-free interest rates	2.78%	—%	2.78% - 2.82%	1.98%
Volatility	83.88%	—%	83.88% - 84.35%	87.10%
Dividend yield	—%	—%	—%	—%

Summary of Stock Option Activity

The Company’s stock options activity for the six months ended October 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, 2018	50,000	2,655,845		2,705,845		$	2.85	5.9	$	5,265,000
Granted	—	141,957		141,957		8.55		9.8
Exercised	—	(380,925	)	(380,925	)	2.16		4.8	2,782,000
Forfeited	—	—		—		—
Canceled	—	—		—		—
Expired	—	—		—		—
Outstanding, October 31, 2018	50,000	2,416,877		2,466,877		3.28		5.9	$	22,630,000
Vested and expected to vest as of October 31, 2018	50,000	2,416,877		2,466,877		3.11		5.9	$	22,630,000
Exercisable as of October 31, 2018	25,836	2,110,961		2,136,797		2.71		5.4	$	20,410,000

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, 2018	2,004,284		$	5.57	1.8	$	—
Granted	—		—		—	—
Exercised	(126,065	)	5.74		—	—
Expired	—		—		—	—
Outstanding, October 31, 2018	1,878,219		$	5.56	1.27	$	—