Net Income (Loss) per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator:
Net income (loss) - basic	$ (53,168)	$ (106,049)	$ (86,839)	$ (162,261)
Net income (loss) - diluted	$ (53,168)	$ (106,049)	$ (86,839)	$ (162,261)
Denominator:
Weighted average common shares outstanding - basic	72,951	64,209	72,113	63,953
Weighted-average common shares outstanding and dilutive potential common shares - diluted	72,951	64,209	72,113	63,953
Net income (loss) per share:
Basic (in dollars per share)	$ (0.73)	$ (1.65)	$ (1.20)	$ (2.54)
Diluted (in dollars per share)	$ (0.73)	$ (1.65)	$ (1.20)	$ (2.54)