Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Schedule of stock-based compensation expense

The amount of stock based compensation expense recognized for the three months ended March 31, 2018 and 2017 as follows:



	Three Months Ended March 31,
	2018		2017
Research and development	$	11,497	$	48,852
General and administrative	207,382		283,367
Sales and marketing	23,945		—
Total stock-based compensation	$	242,824	$	332,219

Summary of option activity

A summary of option activity for the three months ended March 31, 2018 is as follows:



	Options Outstanding
	Number of shares		Weighted average exercise price		Grant date fair value of options		Weighted average remaining contractual term (in years)
Balance at December 31, 2017	2,823,489		$	3.93			7.29
Granted	1,030,070		$	3.77	$	2,335,255
Exercised	(143,148	)	$	2.53
Forfeited	(301,027	)	$	2.21
Balance at March 31, 2018	3,409,384		$	4.09			9.48
Exercisable at March 31, 2018	1,671,978		$	5.03			6.68

Activity for the market-based options was as follows for the three months ended March 31, 2018:



	Options Outstanding
	Number of shares	Weighted average exercise price		Weighted average remaining contractual term (in years)	Aggregate intrinsic value (1)
Balance at December 31, 2017	—
Granted	500,000	$	4.24
Exercised	—
Forfeited	—
Balance at March 31, 2018	500,000	$	4.24	9.99	0
Exercisable at March 31, 2018	—

(1) The aggregate intrinsic value in the above table represents the total pre-tax amount that a participant would receive if the option had been exercised on the last day of the respective fiscal period. Options with a market value less than its exercise value are not included in the intrinsic value amount.

Schedule of fair value assumptions for options

The following table shows the assumptions used to compute stock-based compensation expense for stock options granted to employees and members of the board of directors under the Black-Scholes valuation model, and the assumptions used to compute stock-based compensation expense market-based stock option grants under a Monte Carlo simulation, for the three months ended March 31, 2018:



Service-based options
Expected dividend yield		—%
Expected volatility		55 - 65%
Expected life (in years)		5.0 - 6.25
Risk-free interest rate		2.53 - 2.69%

Market-based options
Expected dividend yield		—%
Expected volatility		60%
Expected life (in years)		10
Risk-free interest rate		2.84%

Nonvested Restricted Stock Shares Activity

The following table summarizes the Company's RSA grants for the three months ended March 31, 2018:



	Non-vested RSAs Outstanding
	Number of shares	Weighted average grant date fair value
Non-vested RSAs at December 31, 2017	—	$	—
Granted	400,000	$	4.24
Vested	—	$	—
Forfeited	—	$	—
Non-vested RSAs at March 31, 2018	400,000