STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2018

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

Schedule of fair values of stock options granted, estimated using Black-Scholes option valuation model assumptions

We estimated the fair value of stock options awarded during the three months ended March 31, 2017 and 2018 using the Black-Scholes option valuation model. The fair values of stock options granted for the periods were estimated using the following assumptions: 

	Stock Option Grants Awarded During the Three Months Ended March 31, 2017	Stock Option Grants Awarded During the Three Months Ended March 31, 2018
Stock Price	$4.36 to $4.37	$5.01 to $5.96
Dividend Yield	0.00%	0.00%
Expected Volatility	60%	70%
Risk-free interest rate	2.09% - 2.14%	2.50% - 2.61%
Expected Life	7 years	7 years

Summary of stock option activity

The following is a summary of our stock option activity during the three months ended March 31, 2018: 

	Number of Options		Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Life In Years
Outstanding, January 1, 2018	1,082,490		$	4.87	$	3.00	8.38
Granted	37,500		5.57		3.77		9.83
Exercised	—		—		—		—
Canceled / Forfeited	(39,838	)	4.56		2.74		—
Outstanding, March 31, 2018	1,080,152		$	4.90	$	3.03	8.03

	Number of Options	Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Life In Years
Exercisable, January 1, 2018	704,303	$	5.08	$	3.17	8.15
Vested	37,470	4.73		2.86		7.84
Exercised	—	—		—		—
Canceled / Forfeited	—	—		—		—
Exercisable, March 31, 2018	741,773	$	5.06	$	3.15	7.72

Schedule of information related to stock options outstanding and exercisable

The following table presents information related to stock options outstanding and exercisable at March 31, 2018: 

Options Outstanding		Options Exercisable
Exercise Price	Outstanding Number of Options	Weighted Average Remaining Life In Years	Exercisable Number of Options
$1.93 – $2.00	149,000	7.85	74,512
$3.83 – $4.70	492,724	8.83	356,640
$5.01 – $6.00	278,128	6.23	201,889
$6.18 – $7.20	70,000	6.52	45,321
$7.54 – $7.80	67,800	6.75	46,058
$8.06 – $12.98	22,500	6.80	17,353
	1,080,152	7.72	741,773

Schedule of restricted stock unit activity

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

	Number of Restricted Share Units		Weighted- Average Grant-Date Fair Value Per Share
Outstanding at January 1, 2018	1,476,858		$	4.96
Granted	270,528		6.08
Vested	(184,818	)	5.32
Forfeited	(6,799	)	4.98
Outstanding at March 31, 2018	1,555,769		$	5.11

Schedule of stock-based compensation

Total equity-based compensation costs recorded in the condensed consolidated statements of operations is allocated as follows: 

	Three Months Ended March 31, 2017		Three Months Ended March 31, 2018
Research and development
Employees	$	226,000	$	536,000
Non-employees	26,000		(5,000		)
Total research and development	252,000		531,000
General and administrative
Employees and directors	367,000		407,000
Non-employees	74,000		25,000
Total general and administrative	441,000		432,000
Total equity-based compensation	$	693,000	$	963,000