STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2016

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

Schedule of weighted average assumptions used to estimate fair value of each service-based stock option grant

The fair value of each service-based stock option grant for the reported periods is estimated on the date of the grant using the Black-Scholes option-pricing model using the weighted average assumptions noted in the following table.

	Six Months Ended June 30,
Service-Based Stock Options	2016		2015
Expected dividend rate	—	%	—	%
Expected stock price volatility	78.7 – 92.2%		78.8 – 88.1%
Risk-free interest rate	1.2 – 1.8%		1.5 – 2.0%
Expected life (years)	5.5 – 6.3		5.5 – 6.3

Summary of activity for service-based stock options

The following table summarizes the activity for service-based stock options for the indicated periods:

Service-Based Stock Options	Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding at December 31, 2015	2,523,400	$	6.36	8.7	$	5,000
Granted	1,072,230	$	3.03
Exercised	39,231	$	3.06		$	76,827
Expired	72,375	$	37.79
Forfeited	113,686	$	3.81
Outstanding at June 30, 2016	3,370,338	$	4.75	7.8	$	150,224
Exercisable at June 30, 2016	900,364	$	8.93	8.6	$	8,439