Net Loss Per Share Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Basic and diluted net loss per share [Abstract]
Net loss (Numerator)	$ (53,443)	$ (62,365)	$ (62,505)	$ (43,447)	$ (14,597)	$ (33,875)	$ (25,474)	$ (30,522)	$ (221,760)	$ (104,468)	$ (67,830)
Weighted-average shares, in thousands (Denominator) (in shares)									90,610	82,926	79,782
Basic and diluted net loss per share (in dollars per share)	$ (0.58)	$ (0.68)	$ (0.69)	$ (0.49)	$ (0.17)	$ (0.41)	$ (0.31)	$ (0.38)	$ (2.45)	$ (1.26)	$ (0.85)
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)									20,942	21,428	20,040
Weighted average exercise price (in dollars per share)									$ 21.21	$ 18.80	$ 17.66
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)									846	526	500
Convertible Senior Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)									939
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)									939