Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components of derivative instruments
MHR Convertible Note	$ 230	$ 7,367
Derivative instruments, net	2,089	10,199
August 2007 Warrants [Member]
Components of derivative instruments
Derivative instruments		12
August 2009 Warrants [Member]
Components of derivative instruments
Derivative instruments	372	540
June 2010 MHR Warrants [Member]
Components of derivative instruments
Derivative instruments	79	351
August 2010 Warrants [Member]
Components of derivative instruments
Derivative instruments	535	735
August 2010 MHR Waiver Warrants [Member]
Components of derivative instruments
Derivative instruments	103	142
July 2011 Warrants [Member]
Components of derivative instruments
Derivative instruments	680	929
July 2011 MHR Waiver Warrants [Member]
Components of derivative instruments
Derivative instruments	$ 90	$ 123