Stock-Based Compensation - Stock Options Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Stock Options [Roll Forward]
Outstanding December 31, 2012 (shares)	5,818,472
Granted (shares)	882,602
Exercised (shares)	0
Canceled (shares)	(201,772)
Forfeited (shares)	(121,738)
Outstanding March 31, 2013 (shares)	6,377,564
Exercisable as of March 31, 2013 (shares)	3,385,768
Weighted Average Exercise Price [Roll Forward]
Oustanding December 31, 2012 (dollars per share)	$ 16.57
Granted (dollars per share)	$ 3.86
Exercised (dollars per share)	$ 0.00
Canceled (dollars per share)	$ 24.53
Forfeited (dollars per share)	$ 7.39
Outstanding March 31, 2013 (dollars per share)	$ 14.73
Exercisable as of March 31, 2013 (dollars per share)	$ 21.90
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 11 months
Total unrecognized compensation expense related to non-vested stock	$ 5.5