Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2014

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


	March 31, 2014		December 31, 2013
2009 Warrants	$	4,637	$	8,542
2010 Warrants		6,719		11,848

Total warrant liability	$	11,356	$	20,390

Fair Value Assumptions of Warrants

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


	March 31, 2014			December 31, 2013
2009 Warrants:
Expected term (in years)		0.40			0.65
Estimated volatility		52	%		45	%
Risk-free interest rate		0.07	%		0.10	%
Expected dividend yield		0	%		0	%
2010 Warrants:
Expected term (in years)		1.61			1.86
Estimated volatility		45	%		41	%
Risk-free interest rate		0.44	%		0.38	%
Expected dividend yield		0	%		0	%