Share-based Compensation - Stock Options (Details) (USD $)	12 Months Ended							3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock Options [Member]	Dec. 31, 2013 Share-based Compensation, Past Plans [Member]	Dec. 31, 2013 Share-based Compensation, Past Plans [Member] Minimum [Member]	Dec. 31, 2013 Share-based Compensation, Past Plans [Member] Maximum [Member]	Dec. 31, 2012 Surrender Agreements [Member] Executive Officer [Member]	Oct. 11, 2012 Surrender Agreements [Member] Executive Officer [Member] Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance					11,375,000
Shares of common stock available for issuance					1,431,172
Vesting period						3 years	4 years
Options exercisable term					10 years
Options weighted average grant date fair value (in usd per share)	$ 5.05	$ 4.95
Expected volatility	74.00%	71.00%
Expected term (in years)	5 years 9 months	5 years 9 months
Risk-free interest rate	1.20%	0.90%
Expected dividend yield	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, number of shares - beginning balance	3,365,000	3,146,000
Options exercisable, number of shares - beginning balance	1,222,000	1,466,000
Options granted, number of shares	226,000	1,453,000
Options forfeited, number of shares	(677,000)	(1,234,000)
Options exercised, number of shares	(828,000)	0
Options outstanding, number of shares - ending balance	2,086,000	3,365,000	3,146,000
Options exercisable, number of shares - ending balance	852,000	1,222,000	1,466,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, weighted average exercise price per share - beginning balance (in usd per share)									$ 50
Options exercisable, weighted average exercise price per share - beginning balance (in usd per share)	$ 23.30	$ 34.71
Options granted, weighted average exercise price per share (in usd per share)	$ 8.06	$ 8.22
Options forfeited, weighted average exercise price per share (in usd per share)	$ 15.49	$ 36.59
Options exercised, weighted average exercise price per share (in usd per share)	$ 8.99	$ 0.00
Options outstanding, weighted average exercise price per share - ending balance (in usd per share)	$ 15.47	$ 14.38	$ 25.93
Options exercisable, weighted average exercise price per share - ending balance (in usd per share)	$ 25.31	$ 23.30	$ 34.71
Options outstanding, weighted average remaining term	5 years 11 months 5 days	6 years 9 months 26 days	6 years 10 months 21 days
Options outstanding, aggregate intrinsic value	$ 11,786,000	$ 433,000	$ 1,012,000
Options exercisable, weighted average remaining contractual term	3 years 1 month 6 days	4 years 2 months 23 days	4 years 9 months 15 days
Options exercisable, aggregate intrinsic value	0	0	0
Unrecognized compensation costs related to unvested awards				6,200,000
Unrecognized compensation costs weighted average period for recognition				2 years 3 months 11 days
Proceeds from stock options exercised	$ 4,600,000	$ 0
Shares surrendered								415,000
Exercise price of shares surrendered, lower range								$ 51.50
Exercise price of shares surrendered, upper range								$ 79