Share-Based Payments (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-Based Payments
Allocated share-based compensation	$ 3,300,000	$ 3,500,000	$ 6,200,000	$ 6,700,000
Additional disclosures
Change in net income (loss)	(28,848,000)	(10,166,000)	(52,965,000)	(15,149,000)
Stock options
Weighted average assumptions used in fair value calculations
Expected volatility (as a percent)	64.00%	70.00%	62.00%	66.00%
Expected life	5 years 1 month 6 days	5 years 8 months 12 days	6 years	6 years 3 months 18 days
Risk-free interest rate (as a percent)	1.70%	1.10%	1.40%	1.30%
Additional disclosures
Remaining unrecognized compensation cost related to nonvested awards	15,000,000		15,000,000
Weighted average remaining requisite service period			2 years 8 months 12 days
2004 Employee Stock Purchase Plan ("ESPP")
Weighted average assumptions used in fair value calculations
Expected volatility (as a percent)	62.00%	65.00%	64.00%	66.00%
Expected life	6 months	6 months	6 months	6 months
Risk-free interest rate (as a percent)	0.10%	0.10%	0.10%	0.10%
Additional disclosures
Exercised (in shares)			120,966
Shares issued during period			38,626
Restricted stock awards
Share-Based Payments
Allocated share-based compensation	1,100,000	1,500,000	2,000,000	2,900,000
Additional disclosures
Remaining unrecognized compensation cost related to nonvested awards	$ 7,500,000		$ 7,500,000
Weighted average remaining requisite service period			1 year 8 months 12 days
Non-vested shares of restricted stock, Number of Shares
Nonvested at the beginning of the period (in shares)			1,137,000
Granted (in shares)			146,000
Vested (in shares)			(83,000)
Forfeited (in shares)			(31,000)
Nonvested at the end of the period (in shares)	1,169,000		1,169,000
Non-vested shares of restricted stock, Weighted Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)			$ 14.61
Granted (in dollars per share)			$ 12.58
Vested (in dollars per share)			$ 14.48
Forfeited (in dollars per share)			$ 14.59
Nonvested at the end of the period (in dollars per share)	$ 14.37		$ 14.37
Time-based restricted stock awards
Share-Based Payments
Award vesting period			4 years
Non-vested shares of restricted stock, Number of Shares
Nonvested at the end of the period (in shares)	322,000		322,000
Time-based restricted stock awards | Officers
Non-vested shares of restricted stock, Number of Shares
Granted (in shares)			140,300
Time-based restricted stock awards | Newly hired employee
Non-vested shares of restricted stock, Number of Shares
Granted (in shares)			5,000
New Hire Awards
Additional disclosures
Granted (in shares)			129,275
Performance-based restricted stock awards
Non-vested shares of restricted stock, Number of Shares
Nonvested at the end of the period (in shares)	847,000		847,000
Performance-based restricted stock awards | Newly hired employee
Non-vested shares of restricted stock, Number of Shares
Granted (in shares)			1,680
Performance-based restricted stock awards, M356
Non-vested shares of restricted stock, Number of Shares
Granted (in shares)			949,620