CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Class A Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2011	$ (49,078)	$ 2	$ 91	$ 1,754,824	$ (1,267,323)	$ (1,862)
Balance (shares) at Dec. 31, 2011		2,109	90,692
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	31,746		2	31,744
Issuance of Common Stock in connection with exercise of stock options (shares)			2,662
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(49,078)			(49,078)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (shares)			(469)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)			64
Conversion of Class A Stock to Common Stock (shares)		(20)	20
Stock-based compensation charges	23,448			23,448
Net income	11,651				11,651
Other Comprehensive Income	525					525
Other comprehensive income (loss), net of tax	525
Balance at Mar. 31, 2012	(30,786)	2	93	1,760,938	(1,255,672)	(1,337)
Balance (shares) at Mar. 31, 2012		2,089	92,969
Balance at Dec. 31, 2012	1,245,385	2	95	1,763,508	(517,054)	(1,166)
Balance (shares) at Dec. 31, 2012		2,069	95,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	9,804			9,804
Issuance of Common Stock in connection with exercise of stock options (shares)			396
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(3,085)			(3,085)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (shares)			(17)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)			38
Conversion of Class A Stock to Common Stock (shares)		(11)	11
Stock-based compensation charges	53,555			53,555
Excess tax benefit from stock-based compensation	2,293			2,293
Net income	98,874				98,874
Other comprehensive income (loss), net of tax	(478)					(478)
Balance at Mar. 31, 2013	$ 1,406,348	$ 2	$ 95	$ 1,826,075	$ (418,180)	$ (1,644)
Balance (shares) at Mar. 31, 2013		2,058	95,651