Stock-Based Compensation - Stock Options Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Stock Options [Roll Forward]
Outstanding December 31, 2012 (shares)	5,818,472
Granted (shares)	1,034,406
Exercised (shares)	0
Canceled (shares)	(1,001,382)
Forfeited (shares)	(382,493)
Outstanding September 30, 2013 (shares)	5,469,003
Exercisable as of September 30, 2013 (shares)	3,411,153
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)	$ 25.67
Forfeited (dollars per share)	$ 7.22
Outstanding September 30, 2013 (dollars per share)	$ 13.14
Exercisable as of September 30, 2013 (dollars per share)	$ 17.65
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 7 months
Total unrecognized compensation expense related to non-vested stock	$ 3.7