Consolidated Statements of Stockholders' Net Capital Deficiency (Equity) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Common Stock Class A Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Comprehensive Income
Balance at Dec. 31, 2008	$ (134,949)	$ 525	$ 94	$ 895,383	$ 501	$ (1,031,452)
Balance (in shares) at Dec. 31, 2008		52,576,000	9,402,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan	11,723	24		11,699
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)		2,254,000
Stock-based compensation	20,000			20,000
Comprehensive loss:
Net loss	(85,302)					(85,302)	(85,302)
Net unrealized gain (loss) on marketable securities	(466)				(466)		(466)
Total comprehensive loss	(85,768)						(85,768)
Balance at Dec. 31, 2009	(188,994)	549	94	927,082	35	(1,116,754)
Balance (in shares) at Dec. 31, 2009		54,830,000	9,402,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan	8,761	17		8,744
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)		1,745,000
Issuance of common stock for cash in secondary stock offering, net of expenses of $5.7 million	93,478	86		93,392
Issuance of common stock for cash in secondary stock offering, net of expenses of $5.7 million (in shares)		8,625,000
Issuance of common stock in private placement to a related party, net of expenses of $0.2 million in 2010	129,190	58		129,132
Issuance of common stock in private placement to a related party, net of expenses of $0.2 million in 2010		5,750,000
Stock-based compensation	19,009			19,009
Comprehensive loss:
Net loss	(83,862)					(83,862)	(83,862)
Net unrealized gain (loss) on marketable securities	(2)				(2)		(2)
Total comprehensive loss	(83,864)						(83,864)
Balance at Dec. 31, 2010	(22,420)	710	94	1,177,359	33	(1,200,616)
Balance (in shares) at Dec. 31, 2010		70,950,000	9,402,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan	12,195	21		12,174
Exercise of stock options, and Issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)		2,134,000
Issuance of common stock in private placement to a related party, net of expenses of $0.2 million in 2010	13,618	5		13,613
Issuance of common stock in private placement to a related party, net of expenses of $0.2 million in 2010		574,000
Conversion of Class A common stock (Note 3)		94	(94)
Conversion of Class A common stock (Note 3) (in shares)		9,402,000	(9,402,000)
Stock-based compensation	24,916	25		24,891
Stock-based compensation (in shares)		2,483,000
Comprehensive loss:
Net loss	(115,344)					(115,344)	(115,344)
Net unrealized gain (loss) on marketable securities	(17)				(17)		(17)
Total comprehensive loss	(115,361)						(115,361)
Balance at Dec. 31, 2011	$ (87,052)	$ 855	$ 0	$ 1,228,037	$ 16	$ (1,315,960)
Balance (in shares) at Dec. 31, 2011		85,543,000	0