Convertible Debentures (Tables)

12 Months Ended

Dec. 31, 2012

Convertible Debentures Disclosure [Abstract]

Schedule of debenture interest paid with cash and principal converted into shares of common stock

Shares issued upon the exercise of warrants, interest paid with cash and principal converted into shares of common stock are as follows (in thousands): 

	Year Ended December 31, 2011			Year Ended December 31, 2010
	Amount		Shares	Amount		Shares
Exercise of warrants	$	—	—	$	7,500	462
Conversion of principal into shares of common stock	$	8,333	514	$	—	—
Interest paid with cash	17		N/A	115		N/A
Total debenture payments	$	8,350	514	$	115	—