Stock-Based Compensation - Stock Option Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Options [Roll Forward]
Exercised (in shares)	(87,569)	0	0
Weighted Average Exercise Price [Roll Forward]
Aggregate Intrinsic Value	$ 0.1	$ 0.8	$ 0.1
Stock Options
Stock Options [Roll Forward]
Outstanding, Beginning Balance (in shares)	5,371,538	5,818,472	5,679,579
Granted (in shares)	61,275	1,034,406	1,178,780
Exercised (in shares)	(87,569)	0	0
Canceled (in shares)	(881,069)	(1,069,192)	(752,415)
Forfeited (in shares)	(566,189)	(412,148)	(287,472)
Outstanding, Ending Balance (in shares)	3,897,986	5,371,538	5,818,472	5,679,579
Weighted Average Exercise Price [Roll Forward]
Oustanding, Beginning Balance (dollars per share)	$ 13.11	$ 16.57	$ 19.87
Granted (dollars per share)	$ 3.72	$ 3.85	$ 5.80
Exercised (dollars per share)	$ 3.97	$ 0.00	$ 0.00
Canceled (dollars per share)	$ 19.05	$ 25.22	$ 26.61
Forfeited (dollars per share)	$ 4.14	$ 7.13	$ 9.24
Outstanding, Ending Balance (dollars per share)	$ 13.07	$ 13.11	$ 16.57	$ 19.87
Weighted Average Remaining Contractual Life (Years)	4 years 9 months 18 days	6 years 1 month 6 days	5 years 10 months 24 days	6 years
Aggregate Intrinsic Value	$ 0	$ 0.8	$ 0	$ 0