DERIVATIVE INSTRUMENTS (Tables)

9 Months Ended

Sep. 30, 2016

DERIVATIVE INSTRUMENTS

Assumptions used in determining fair value of warrants

	September 30,		December 31,
	2016		2015
Risk free interest rate	0.90	%	0.65	%
Expected dividend yield	0.00	%	0.00	%
Expected term (in years)	2.61		3.36
Expected volatility	92.67	%	100.20	%

Changes in derivative warrant liability

Changes in the derivative warrant liability for the three and nine months ended September 30,  2016 and 2015 are as follows (in thousands):

	Three Months Ended September 30,
	2016		2015
Balance at June 30,	$	2,359	$	7,722
Fair value of warrants issued		—		—
Reduction in derivative liability due to exercise and modification of warrants		—		(1,680)
Increase (decrease) in the fair value of warrants		336		(3,591)
Balance at September 30,	$	2,695	$	2,451

	Nine Months Ended September 30,
	2016		2015
Balance at December 31,	$	1,907	$	7,224
Fair value of warrants issued		—		—
Reduction in derivative liability due to exercise and modification of warrants		—		(16,122)
Increase in the fair value of warrants		788		11,349
Balance at September 30,	$	2,695	$	2,451