Warrants (Tables)

6 Months Ended

Jun. 30, 2013

Number of Warrants Outstanding

The number of warrants outstanding at June 30, 2013 and December 31, 2012 were as follows:

	June 30, 2013		December 31, 2012
Liability-classified warrants		8,050,709		8,050,709
Equity-classified warrants		2,390,722		3,146,745
Total warrants		10,441,431		11,197,454

Assumptions Used In Binomial and Monte Carlo Valuation Model

The following assumptions were used in the Binomial/Monte Carlo valuation model at June 30, 2013 and 2012:

	June 30, 2013			June 30, 2012
Risk-free interest rate		0.26	%		0.37	%
Expected life in years		1.44			2.44
Expected volatility		70	%		70	%
Expected dividend yield		0			0
Steps per year		12			12

Warrant Exercises

During the six months ended June 30, 2013, warrant exercises were as follows:

(in thousands, except share data)	Equity Warrants		Liability Warrants		Common Stock Issued		Liability Reclassed to Equity		Cash Received
Cash exercises		49,315		—		49,315	$	—	$	101
Cashless exercises		—		—		—		—		—
		49,315		—		49,315	$	—	$	101

During the six months ended June 30, 2012, warrant exercises were as follows:

(in thousands, except share data)	Equity Warrants		Liability Warrants		Common Stock Issued		Liability Reclassed to Equity		Cash Received
Cash exercises		102,744		—		102,744	$	—	$	210
Cashless exercises		12,329		373,617		89,859		412		—
		115,073		373,617		192,603	$	412	$	210