CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (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, 2010	$ 527,815	$ 2	$ 87	$ 1,575,780	$ (1,045,563)	$ (2,491)
Balance, shares at Dec. 31, 2010		2,182	87,238
Increase (decrease) in stockholders' equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options (in shares)			3,284
Issuance of Common Stock in connection with exercise of stock options	40,138		3	40,135
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)			(284)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(16,316)			(16,316)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)			92
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	3,405			3,405
Issuance of restricted Common Stock under Long-Term Incentive Plan (in shares)			16
Issuance of restricted Common Stock under Long-Term Incentive Plan
Conversion of Class A Stock to Common Stock (in shares)		(73)	73
Conversion of Class A Stock to Common Stock
Stock-based compensation charges	40,768			40,768
Net income (loss)	(168,317)				(168,317)
Other comprehensive income (loss), net of tax	760					760
Balance at Sep. 30, 2011	428,253	2	90	1,643,772	(1,213,880)	(1,731)
Balance, shares at Sep. 30, 2011		2,109	90,419
Balance at Dec. 31, 2011	485,732	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 (in shares)			3,773
Issuance of Common Stock in connection with exercise of stock options	48,440		4	48,436
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)			(639)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(71,475)		(1)	(71,474)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)			64
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution
Issuance of restricted Common Stock under Long-Term Incentive Plan (in shares)			500
Issuance of restricted Common Stock under Long-Term Incentive Plan
Conversion of Class A Stock to Common Stock (in shares)		(20)	20
Conversion of Class A Stock to Common Stock
Stock-based compensation charges	63,507			63,507
Net income (loss)	279,862				279,862
Other comprehensive income (loss), net of tax	(42)					(42)
Balance at Sep. 30, 2012	$ 806,024	$ 2	$ 94	$ 1,795,293	$ (987,461)	$ (1,904)
Balance, shares at Sep. 30, 2012		2,089	94,410