Stock-Based Compensation - Stock Options Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Stock Options [Roll Forward]
Outstanding December 31, 2012 (shares)	5,818,472
Granted (shares)	1,026,674
Exercised (shares)	0
Canceled (shares)	(917,002)
Forfeited (shares)	(300,896)
Outstanding June 30, 2013 (shares)	5,627,248
Exercisable as of June 30, 2013 (shares)	3,480,411
Weighted Average Exercise Price [Roll Forward]
Oustanding December 31, 2012 (dollars per share)	$ 16.57
Granted (dollars per share)	$ 3.85
Exercised (dollars per share)	$ 0.00
Canceled (dollars per share)	$ 25.99
Forfeited (dollars per share)	$ 7.70
Outstanding June 30, 2013 (dollars per share)	$ 13.18
Exercisable as of June 30, 2013 (dollars per share)	$ 17.81
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expiration term	10 years
Total compensation cost not yet recognized, period for recognition	1 year 9 months
Total unrecognized compensation expense related to non-vested stock	$ 4.5