Consolidated Statements of Stockholders' Equity (Net Capital Deficiency) (USD $) In Thousands, except Share data, unless otherwise specified	Total USD ($)	Common Stock	Class A Common Stock	Common Stock USD ($)	Common Stock Class A Common Stock USD ($)	Additional Paid-In Capital USD ($)	Accumulated Other Comprehensive Income USD ($)	Accumulated Deficit USD ($)
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			46	0	12,149	0	0
Exercise of stock options, and issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)				4,617,000	0
Issuance of common stock in private placement to a related party	13,618			5	0	13,613	0	0
Issuance of common stock in private placement to a related party, net of expenses (in shares)				574,000	0
Conversion of convertible subordinated notes due 2015	0					0	0	0
Conversion of Class A common stock				94	(94)
Conversion of Class A common stock (in shares)				9,402,000	(9,402,000)
Stock-based compensation	24,916			0	0	24,916	0	0
Net loss	(115,344)			0	0	0	0	(115,344)
Net unrealized gain (loss) on marketable securities	(17)			0	0	0	(17)	0
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
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	7,081			22	0	7,059	0	0
Exercise of stock options, and issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)				2,151,000	0
Issuance of common stock in private placement to a related party	229,296			107	0	229,189	0	0
Issuance of common stock in private placement to a related party, net of expenses (in shares)				10,685,000	0
Stock-based compensation	24,162			0	0	24,162	0	0
Net loss	(18,542)			0	0	0	0	(18,542)
Net unrealized gain (loss) on marketable securities	83			0	0	0	83	0
Balance at Dec. 31, 2012	155,028			984	0	1,488,447	99	(1,334,502)
Balance (in shares) at Dec. 31, 2012		98,379,000	0	98,379,000	0
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	26,991			29	0	26,962	0	0
Exercise of stock options, and issuance of common stock in settlement of restricted stock units, stock awards and purchase plan (in shares)				2,964,000	0
Issuance of common stock in private placement to a related party	126,030			35	0	125,995	0	0
Issuance of common stock in private placement to a related party, net of expenses (in shares)				3,505,000	0
Conversion of convertible subordinated notes due 2015	171,231			67	0	171,164	0	0
Conversion of convertible subordinated notes due 2015 (in shares)				6,668,000	0
Stock-based compensation	25,858			0	0	25,858	0	0
Capped call options associated with convertible subordinated notes due 2023	(35,378)			0	0	(35,378)	0	0
Net loss	(170,701)			0	0	0	0	(170,701)
Net unrealized gain (loss) on marketable securities	63			0	0	0	63	0
Balance at Dec. 31, 2013	$ 299,122			$ 1,115	$ 0	$ 1,803,048	$ 162	$ (1,505,203)
Balance (in shares) at Dec. 31, 2013		111,516,000	0	111,516,000	0