Warrants (Tables)

9 Months Ended

Sep. 30, 2014

Number of Warrants Outstanding

The number of warrants outstanding at September 30, 2014 and December 31, 2013 were as follows:

	September 30, 2014		December 31, 2013
Liability-classified warrants		8,235,076		8,235,076
Equity-classified warrants		—		2,304,691
Total warrants		8,235,076		10,539,767

Assumptions Used in Binomial and Monte Carlo Valuation Model

The following assumptions were used in the Binomial/Monte Carlo valuation model at September 30, 2014 and 2013:

	September 30,
	2014			2013
Risk-free interest rate		0.02	%		0.10	%
Expected life in years		0.19			1.19
Expected volatility		65	%		75	%
Expected dividend yield		0			0
Steps per year		125			13

Warrant Exercises

During the nine months ended September 30, 2014, warrant exercises were as follows:

					Common		Liability
	Equity		Liability		Stock		Reclassed		Cash
(in thousands, except share data)	Warrants		Warrants		Issued		to Equity		Received
Cash exercises		1,813,707		—		1,813,707	$	—	$	3,700
Cashless exercises		478,655		—		177,702		—		—
		2,292,362		—		1,991,409	$	—	$	3,700

During the nine months ended September 30, 2013, warrant exercises were as follows:

					Common		Liability
	Equity		Liability		Stock		Reclassed		Cash
(in thousands, except share data)	Warrants		Warrants		Issued		to Equity		Received
Cash exercises		98,359		—		98,359	$	—	$	201
Cashless exercises		—		—		—		—		—
		98,359		—		98,359	$	—	$	201