CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands	Total	Class A Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Comprehensive Loss [Member]
Balance at Dec. 31, 2009	$ 396,762	$ 2	$ 79	$ 1,336,732	$ (941,095)	$ 1,044
Balance (in shares) at Dec. 31, 2009		2,245	78,861
Increase (decrease) in stockholders' equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options, net of shares tendered	13,194		1	13,193
Issuance of Common Stock in connection with exercise of stock options, net of shares tendered (in shares)			993
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	2,867			2,867
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)			111
Issuance of restricted Common Stock under Long-Term Incentive Plan
Issuance of restricted Common Stock under Long-Term Incentive Plan (in shares)			15
Conversion of Class A Stock to Common Stock
Conversion of Class A Stock to Common Stock (in shares)		(63)	63
Stock-based compensation charges	26,331			26,331
Net loss	(89,871)				(89,871)		(89,871)
Change in net unrealized gain (loss) on marketable securities	(1,219)					(1,219)	(1,219)
Total comprehensive loss	(91,090)
Balance at Sep. 30, 2010	348,064	2	80	1,379,123	(1,030,966)	(175)	(91,090)
Balance (in shares) at Sep. 30, 2010		2,182	80,043
Balance at Dec. 31, 2010	527,815	2	87	1,575,780	(1,045,563)	(2,491)
Balance (in 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, net of shares tendered	23,822		3	23,819
Issuance of Common Stock in connection with exercise of stock options, net of shares tendered (in shares)			3,000
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	3,405			3,405
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)			92
Issuance of restricted Common Stock under Long-Term Incentive Plan
Issuance of restricted Common Stock under Long-Term Incentive Plan (in shares)			16
Conversion of Class A Stock to Common Stock
Conversion of Class A Stock to Common Stock (in shares)		(73)	73
Stock-based compensation charges	40,768			40,768
Net loss	(168,317)				(168,317)		(168,317)
Change in net unrealized gain (loss) on marketable securities	760					760	760
Total comprehensive loss	(167,557)
Balance at Sep. 30, 2011	$ 428,253	$ 2	$ 90	$ 1,643,772	$ (1,213,880)	$ (1,731)	$ (167,557)
Balance (in shares) at Sep. 30, 2011		2,109	90,419