Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Preferred Stock	Common Stock	Treasury Shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained Earnings
Balance at Dec. 31, 2012	$ 757,039		$ 163	$ (350,000)	$ 789,719	$ (2,975)	$ 320,132
Balance (in shares) at Dec. 31, 2012			65,114,000	16,042,000
Increase (Decrease) in Stockholders' Equity
Exercise of common stock options	8,376		1		8,375
Exercise of common stock options (in shares)			686,000
Conversion of senior convertible notes	11				11
Conversion of senior convertible notes (in shares)			1,000
Restricted stock vested (in shares)			34,000
Employee stock purchase plan	558				558
Employee stock purchase plan (in shares)			28,000
Share-based compensation	18,912				18,912
Other comprehensive loss	(127)					(127)
Stock option tax benefits	2,352				2,352
Net loss	(59,212)						(59,212)
Balance at Sep. 30, 2013	$ 727,909	$ 0	$ 164	$ (350,000)	$ 819,927	$ (3,102)	$ 260,920
Balance (in shares) at Sep. 30, 2013		0	65,863,000	16,042,000