Quarterly Financial Information (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information (unaudited)
Revenues	$ 1,090	$ 91	$ 91	$ 208	$ 42	$ 11	$ 750		$ 1,480	$ 803	$ 106
Total costs and expenses	13,834	12,381	9,348	8,086	10,285	9,926	9,146	9,198	43,649	38,555	40,229
(Loss) income from continuing operations	(13,512)	(13,482)	(10,013)	(9,277)	5,581	(10,151)	(8,940)	(9,715)	(46,284)	(23,225)	(39,075)
(Loss) income from discontinued operations					76,394	417	1,563	(1,334)		77,040	612
Net (loss) income	(13,512)	(13,482)	(10,013)	(9,277)	81,975	(9,734)	(7,377)	(11,049)	(46,284)	53,815	(38,463)
Net loss per share, basic and diluted (in dollars per share)	$ (0.51)	$ (0.55)	$ (0.61)	$ (6.05)					$ (2.72)	$ 31.39	$ (26.38)
Net (loss) income per share, basic, continuing operations (in dollars per share)					$ 2.88	$ (6.90)	$ (6.15)	$ (6.64)
Net (loss) income per share, basic, discontinued operations (in dollars per share)					$ 46.64	$ 0.26	$ 0.98	$ (0.84)
Net (loss) income per share, diluted, continuing operations (in dollars per share)					$ 2.34	$ (6.90)	$ (6.15)	$ (6.64)
Net (loss) income per share, diluted, discontinued operations (in dollars per share)					$ 37.80	$ 0.26	$ 0.98	$ (0.84)
Net loss from continuing operations					(10,600)				(46,284)	(39,470)	(39,474)
Tax benefit					$ (16,200)				$ 0	$ (16,245)	$ (399)