Consolidated Statements Of Stockholders' Equity (USD $) In Thousands, except Share data	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balances, value at Dec. 31, 2008	$ 80	$ 394,338	$ (314,022)	$ (1,378)	$ 79,018
Balances, shares at Dec. 31, 2008	79,791,000
Net loss	0	0	(81,683)	0	(81,683)
Unrealized gain (loss), net of amount recognized as an other-than-temporary impairment	0	0	0	129	129
Comprehensive loss	0	0	0	0	(81,554)
Issuance of common stock for employee stock purchase plan, value	0	1,240	0	0	1,240
Issuance of common stock for employee stock purchase plan, shares	146,000				146,692
Stock option exercises, value	1	3,505	0	0	3,506
Stock option exercises, shares	654,000
Issuance of common stock, value	20	192,121	0	0	192,141
Issuance of common stock, shares	19,568,000
Warrant exercise, value	0	0	0	0	0
Warrant exercise, shares	395,000
Share-based compensation	0	11,849	0	0	11,849
Balances, value at Dec. 31, 2009	101	603,053	(395,705)	(1,249)	206,200
Balances, shares at Dec. 31, 2009	100,554,000
Net loss	0	0	(66,265)	0	(66,265)
Unrealized gain (loss), net of amount recognized as an other-than-temporary impairment	0	0	0	(124)	(124)
Comprehensive loss	0	0	0	0	(66,389)
Issuance of common stock for employee stock purchase plan, value	0	1,506	0	0	1,506
Issuance of common stock for employee stock purchase plan, shares	173,000				173,379
Stock option exercises, value	1	5,870	0	0	5,871
Stock option exercises, shares	880,000
Share-based compensation	0	14,330	0	0	14,330
Balances, value at Dec. 31, 2010	102	624,759	(461,970)	(1,373)	161,518
Balances, shares at Dec. 31, 2010	101,607,000				101,607,000
Net loss	0	0	(152,030)	0	(152,030)
Unrealized gain (loss), net of amount recognized as an other-than-temporary impairment	0	0	0	1,393	1,393
Comprehensive loss	0	0	0	0	(150,637)
Issuance of common stock for employee stock purchase plan, value	0	2,526	0	0	2,526
Issuance of common stock for employee stock purchase plan, shares	229,000				229,014
Stock option exercises, value	2	12,325	0	0	12,327
Stock option exercises, shares	1,670,000
Issuance of common stock, value	11	168,042	0	0	168,053
Issuance of common stock, shares	11,500,000
Warrant exercise, value	1	5,077	0	0	5,078
Warrant exercise, shares	1,017,000
Share-based compensation	0	19,984	0	0	19,984
Balances, value at Dec. 31, 2011	$ 116	$ 832,713	$ (614,000)	$ 20	$ 218,849
Balances, shares at Dec. 31, 2011	116,023,000				116,023,000