Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value of Warrants Outstanding

The fair value of the warrants outstanding at December 31, 2014 and 2013, consisted of the following (in thousands):

	December 31,
	2014		2013
2009 Warrants	$	—	$	8,542
2010 Warrants		10,485		11,848
Total warrant liability	$	10,485	$	20,390

Fair Value Assumptions of Warrants

The fair value of the Company’s warrants was based on option valuation model and using the following assumptions at December 31, 2014 and 2013:

	December 31, 2014	December 31, 2013
2009 Warrants:
Expected term (in years)	—	0.65
Estimated volatility	—	45%
Risk-free interest rate	—	0.10%
Expected dividend yield	—	0%
	December 31, 2014	December 31, 2013
2010 Warrants:
Expected term (in years)	0.86	1.86
Estimated volatility	55%	41%
Risk-free interest rate	0.25%	0.38%
Expected dividend yield	0%	0%