Consolidated Statements of Stockholders' Equity (Deficit) (USD $) In Thousands, except Share data	Total	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Series C Convertible Preferred Stock Issuable	Series C Convertible Preferred Stock Subscriptions Receivable	Common Stock	Additional Paid-in Capital	Notes Receivable from Stockholders	Notes Receivable from Officers	Other Comprehensive Income (Loss)	Deficit Accumulated During the Development Stage
Beginning Balance at Feb. 13, 1991
Issuance of common stock (in shares)						998,000
Issuance of common stock	$ 900					$ 10	$ 890
Net loss	(911)										(911)
Ending Balance at Feb. 29, 1992	(11)					10	890				(911)
Ending Balance (in shares) at Feb. 29, 1992						998,000
Capital contribution	20						20
Issuance of common stock (in shares)						73,000
Issuance of common stock	888					1	887
Net loss	(1,175)										(1,175)
Ending Balance at Feb. 28, 1993	(278)					11	1,797				(2,086)
Ending Balance (in shares) at Feb. 28, 1993						1,071,000
Issuance of stock for notes receivable (in shares)						8,000
Issuance of common stock (in shares)						11,000
Issuance of common stock	526						526
Issuance of stock for notes receivable							400	(400)
Net loss	(1,156)										(1,156)
Ending Balance at Feb. 28, 1994	(908)					11	2,723	(400)			(3,242)
Ending Balance (in shares) at Feb. 28, 1994						1,090,000
Collection of stock subscription	400							400
Issuance of common stock (in shares)						36,000
Issuance of common stock	1,805						1,805
Net loss	(2,004)										(2,004)
Ending Balance at Dec. 31, 1994	(707)					11	4,528				(5,246)
Ending Balance (in shares) at Dec. 31, 1994						1,126,000
Issuance of common stock for services	8						8
Exercise of stock options (in shares)						1,000
Exercise of stock options	22						22
Stock-based compensation	384						384
Net loss	(2,815)										(2,815)
Ending Balance at Dec. 31, 1995	(3,108)					11	4,942				(8,061)
Ending Balance (in shares) at Dec. 31, 1995						1,127,000
Issuance of common stock (in shares)						1,000
Issuance of common stock	59						59
Exercise of stock options (in shares)						3,000
Exercise of stock options	12						12
Stock-based compensation	126						126
Net loss	(2,570)										(2,570)
Ending Balance at Dec. 31, 1996	(5,481)					11	5,139				(10,631)
Ending Balance (in shares) at Dec. 31, 1996						1,131,000
Conversion of notes payable (in shares)						12,000
Conversion of notes payable	60						60
Issuance of common stock (in shares)						548,000
Issuance of common stock	196					6	190
Exercise of stock options (in shares)						27,000
Exercise of stock options	135						135
Stock-based compensation	2						2
Net loss	(2,280)										(2,280)
Ending Balance at Dec. 31, 1997	(7,368)					17	5,526				(12,911)
Ending Balance (in shares) at Dec. 31, 1997						1,718,000
Conversion of notes payable (in shares)						215,000
Conversion of notes payable	1,202					2	1,200
Issuance of common stock (in shares)						2,253,000
Issuance of common stock	12,726					23	12,703
Exercise of stock options (in shares)						68,000
Exercise of stock options	25					1	24
Stock-based compensation	150						150
Net loss	(3,331)										(3,331)
Ending Balance at Dec. 31, 1998	3,404					43	19,603				(16,242)
Ending Balance (in shares) at Dec. 31, 1998						4,254,000
Conversion of notes payable (in shares)						80,000
Conversion of notes payable	995					1	994
Issuance of common stock (in shares)						162,000
Issuance of common stock	534					2	532
Net loss	(5,679)										(5,679)
Ending Balance at Dec. 31, 1999	(746)					46	21,129				(21,921)
Ending Balance (in shares) at Dec. 31, 1999						4,496,000
Conversion of notes payable (in shares)						63,000
Conversion of notes payable	1,074					1	1,073
Issuance of Series B preferred stock for cash (in shares)		193,000
Issuance of Series B preferred stock for cash	15,000	15,000
Issuance of common stock (in shares)						4,690,000
Issuance of common stock	31,633					46	33,945	(2,358)
Discount on notes below market rate	241							241
Amount in excess of redemption obligation	999						999
Accrued interest on notes	(117)							(117)
Beneficial conversion feature of Series A/B convertible preferred stock	(993)						(993)
Accretion to redemption value on Series A redeemable convertible preferred stock	(149)						(149)
Stock-based compensation	9,609						9,609
Net loss	(24,661)										(24,661)
Ending Balance at Dec. 31, 2000	31,890	15,000				93	65,613	(2,234)			(46,582)
Ending Balance (in shares) at Dec. 31, 2000		193,000				9,249,000
Issuance of common stock (in shares)						3,052,000
Issuance of common stock	78,030					30	78,000
Issuance of common stock for services (in shares)						3,000
Issuance of common stock for services	60						60
Exercise of stock options (in shares)						1,000
Exercise of stock options	13						13
Cash received for common stock issuable	3,900						3,900
Issuance of put option by stockholder	(2,949)						(2,949)
Payments on notes receivable	28							28
Record merger of entities	171,154						171,154
Accrued interest on notes	(189)							(189)
Accretion to redemption value on Series A redeemable convertible preferred stock	(239)						(239)
Stock-based compensation	1,565						1,565
Net loss	(48,245)										(48,245)
Ending Balance at Dec. 31, 2001	235,018	15,000				123	317,117	(2,395)			(94,827)
Ending Balance (in shares) at Dec. 31, 2001		193,000				12,305,000
Issuance of common stock (in shares)						3,922,000
Issuance of common stock	58,815					40	58,775
Issuance of common stock for cash already received (in shares)						234,000
Issuance of common stock for cash already received						2	(2)
Cash received for common stock issuable	98						98
Issuance of stock award to employee/consultants (in shares)						3,000
Issuance of stock award to employee/consultants	84						84
Payments on notes receivable	1,314							1,314
Put option redemption by stockholder	1,921						1,921
Accrued interest on notes	(229)							(229)
Deemed dividend related to beneficial conversion feature of convertible preferred stock	(1,421)						(1,421)
Beneficial conversion feature of Series A/B convertible preferred stock	1,421						1,421
Accretion to redemption value on Series A redeemable convertible preferred stock	(251)						(251)
Stock-based compensation	268						268
Net loss	(206,265)										(206,265)
Ending Balance at Dec. 31, 2002	90,773	15,000				165	378,010	(1,310)			(301,092)
Ending Balance (in shares) at Dec. 31, 2002		193,000				16,464,000
Conversion of notes payable				50,000	(50,000)
Issuance of common stock (in shares)						3,494,000
Issuance of common stock	50,000					35	49,965
Issuance of common stock for cash already received (in shares)						17,000
Non-cash compensation expense of officer resulting from stockholder contribution	70						70
Issuance of common stock for cash already received	31,847				31,847
Notes receivable by stockholder issued to officers							225		(225)
Put shares sold to majority stockholder	623						623
Accrued interest on notes	(105)							(102)	(3)
Deemed dividend related to beneficial conversion feature of convertible preferred stock	(1,017)						(1,017)
Beneficial conversion feature of Series A/B convertible preferred stock	1,017						1,017
Accretion to redemption value on Series A redeemable convertible preferred stock	(253)						(253)
Stock-based compensation	4,501						4,501
Net loss	(65,879)										(65,879)
Ending Balance at Dec. 31, 2003	111,577	15,000		50,000	(18,153)	200	433,141	(1,412)	(228)		(366,971)
Ending Balance (in shares) at Dec. 31, 2003		193,000				19,975,000
Conversion of notes payable (in shares)			356,000
Conversion of notes payable	18,153		18,153	(18,153)	18,153
Issuance of common stock for cash already received (in shares)			624,000
Issuance of common stock for cash already received			31,847	(31,847)
Exercise of stock options (in shares)						86,000
Exercise of stock options	1,079						1,079
Exercise of warrants (in shares)						4,000
Exercise of warrants	46						46
Repayment of notes receivable by stockholder issued to officers	3						(225)		228
Repayment of stock note receivable (in shares)						(90,000)
Repayment of stock note receivable						(1)	(1,518)	1,519
Conversion of Series A convertible preferred stock to common stock (in shares)						891,000
Conversion of Series A convertible preferred stock to common stock	5,248					9	5,239
Conversion of Series B convertible preferred stock to common stock (in shares)		(193,000)				811,000
Conversion of Series B convertible preferred stock to common stock		(15,000)				8	14,992
Conversion of Series C convertible preferred stock to common stock (in shares)			(980,000)			4,464,000
Conversion of Series C convertible preferred stock to common stock			(50,000)			45	49,955
Issuance of common shares in exchange for warrants (in shares)						22,000
Issuance of common shares under Employee Stock Purchase Plan (in shares)						36,000
Issuance of common shares under Employee Stock Purchase Plan	430						430
Accrued interest on notes	(107)							(107)
Issuance of common shares pursuant to underwritten public offerings (in shares)						6,557,000
Issuance of common shares pursuant to underwritten public offerings	83,176					66	83,110
Deemed dividend related to beneficial conversion feature of convertible preferred stock	(19,822)						(19,822)
Beneficial conversion feature of Series A/B convertible preferred stock	19,822						19,822
Accretion to redemption value on Series A redeemable convertible preferred stock	(60)						(60)
Stock-based compensation	6,810						6,810
Net loss	(75,992)										(75,992)
Ending Balance at Dec. 31, 2004	150,363					327	592,999				(442,963)
Ending Balance (in shares) at Dec. 31, 2004						32,756,000
Issuance of common shares in exchange for warrants	245						245
Issuance of common stock (in shares)						17,132,000
Issuance of common stock	170,234					171	170,063
Exercise of stock options (in shares)						304,000
Exercise of stock options	1,951					3	1,948
Issuance of stock award to employee/consultants (in shares)						40,000
Issuance of stock award to employee/consultants	(145)					1	(146)
Issuance of common shares in exchange for warrants (in shares)						24,000
Issuance of common shares under Employee Stock Purchase Plan (in shares)						58,000
Issuance of common shares under Employee Stock Purchase Plan	495					1	494
Stock-based compensation	(1,828)						(1,828)
Net loss	(114,338)										(114,338)
Ending Balance at Dec. 31, 2005	206,977					503	763,775				(557,301)
Ending Balance (in shares) at Dec. 31, 2005						50,314,000
Issuance of common shares from the release of restricted stock units (in shares)						102,000
Issuance of common shares from the release of restricted stock units	(340)					1	(341)
Issuance of common stock (in shares)						23,000,000
Issuance of common stock	384,670					230	384,440
Exercise of stock options (in shares)						263,000
Exercise of stock options	2,312					3	2,309
Exercise of warrants (in shares)						339,000
Cancellation of common shares for stock notes receivable (in shares)						(844,000)
Exercise of warrants	2,694					3	2,691
Cancellation of common shares for stock notes receivable						(8)	8
Issuance of common shares pursuant to research agreement (in shares)						100,000
Issuance of common shares pursuant to research agreement	2,074					1	2,073
Issuance of common shares under Employee Stock Purchase Plan (in shares)						86,000
Issuance of common shares under Employee Stock Purchase Plan	981					1	980
Stock-based compensation	14,667						14,667
Net loss	(230,548)										(230,548)
Ending Balance at Dec. 31, 2006	383,487					734	1,170,602				(787,849)
Ending Balance (in shares) at Dec. 31, 2006						73,360,000
Issuance of common shares from the release of restricted stock units (in shares)						146,000
Issuance of common shares from the release of restricted stock units	(524)					2	(526)
Issuance of common stock (in shares)						27,014,000
Issuance of common stock	249,750					270	249,480
Exercise of stock options (in shares)						607,000
Exercise of stock options	4,923					6	4,917
Issuance of stock award to employee/consultants (in shares)						30,000
Issuance of stock award to employee/consultants	123						123
Issuance of common shares pursuant to research agreement (in shares)						100,000
Issuance of common shares pursuant to research agreement	944					1	943
Issuance of common shares under Employee Stock Purchase Plan (in shares)						124,000
Issuance of common shares under Employee Stock Purchase Plan	1,065					1	1,064
Stock-based compensation	17,522						17,522
Net loss	(293,190)										(293,190)
Ending Balance at Dec. 31, 2007	364,100					1,014	1,444,125				(1,081,039)
Ending Balance (in shares) at Dec. 31, 2007						101,381,000
Issuance of common shares from the release of restricted stock units (in shares)						248,000
Issuance of common shares from the release of restricted stock units	(315)					2	(317)
Issuance of stock award to employee/consultants (in shares)						30,000
Issuance of stock award to employee/consultants	(18)						(18)
Unrealized gain/(loss) on available-for-sale securities	295									295
Issuance of common shares under Employee Stock Purchase Plan (in shares)						349,000
Issuance of common shares under Employee Stock Purchase Plan	900					4	896
Stock-based compensation	24,811						24,811
Net loss	(303,039)										(303,039)
Ending Balance at Dec. 31, 2008	86,734					1,020	1,469,497			295	(1,384,078)
Ending Balance (in shares) at Dec. 31, 2008						102,008,000
Issuance of common shares from the release of restricted stock units (in shares)						2,240,000
Issuance of common shares from the release of restricted stock units	(7,001)					22	(7,023)
Issuance of common stock (in shares)						8,360,000
Issuance of common stock	59,724					84	59,640
Exercise of stock options (in shares)						94,000
Exercise of stock options	383					1	382
Unrealized gain/(loss) on available-for-sale securities	(581)									(581)
Issuance of common shares under Employee Stock Purchase Plan (in shares)						323,000
Issuance of common shares under Employee Stock Purchase Plan	1,400					3	1,397
Unrealized gain/(loss) on foreign currency translation	5									5
Stock-based compensation	20,219						20,219
Net loss	(220,104)										(220,104)
Ending Balance at Dec. 31, 2009	(59,221)					1,130	1,544,112			(281)	(1,604,182)
Ending Balance (in shares) at Dec. 31, 2009						113,025,000
Conversion of notes payable (in shares)						2,100,000
Conversion of notes payable	16,681					21	16,660
Issuance of common shares from the release of restricted stock units (in shares)						962,000
Issuance of common shares from the release of restricted stock units	(3,392)					10	(3,402)
Issuance of common stock (in shares)						2,100,000
Issuance of common stock	14,335					21	14,314
Exercise of stock options (in shares)						318,000
Exercise of stock options	924					3	921
Issuance of stock under share lending agreement (in shares)						9,000,000
Issuance of stock under share lending agreement	161					90	71
Unrealized gain/(loss) on available-for-sale securities	361									361
Issuance of common shares under Employee Stock Purchase Plan (in shares)	287,597					288,000
Issuance of common shares under Employee Stock Purchase Plan	1,605					3	1,602
Unrealized gain/(loss) on foreign currency translation	(6)									(6)
Stock-based compensation	13,580						13,580
Net loss	(170,560)										(170,560)
Ending Balance at Dec. 31, 2010	(185,532)					1,278	1,587,858			74	(1,774,742)
Ending Balance (in shares) at Dec. 31, 2010						127,793,000
Conversion of notes payable (in shares)						1,400,000
Conversion of notes payable	11,116					14	11,102
Issuance of common shares from the release of restricted stock units (in shares)						433,000
Issuance of common shares from the release of restricted stock units	(543)					4	(547)
Issuance of common stock (in shares)						1,400,000
Issuance of common stock	9,540					14	9,526
Exercise of stock options (in shares)						214,000
Exercise of stock options	628					2	626
Unrealized gain/(loss) on available-for-sale securities	(27)									(27)
Issuance of common shares under Employee Stock Purchase Plan (in shares)	282,816					283,000
Issuance of common shares under Employee Stock Purchase Plan	769					3	766
Unrealized gain/(loss) on foreign currency translation	(3)									(3)
Stock-based compensation	11,204						11,204
Net loss	(160,804)										(160,804)
Ending Balance at Dec. 31, 2011	(313,652)					1,315	1,620,535			44	(1,935,546)
Ending Balance (in shares) at Dec. 31, 2011						131,523,000
Conversion of notes payable (in shares)						71,250,000
Conversion of notes payable	184,537					713	183,824
Issuance of common shares from the release of restricted stock units (in shares)						886,000
Issuance of common shares from the release of restricted stock units	(906)					9	(915)
Exercise of stock options (in shares)	3,216					3,000
Exercise of stock options	9						9
Fair value of forward purchase contracts	1,237						1,237
Issuance of common shares pursuant to litigation settlement (in shares)						225,000
Issuance of common shares pursuant to litigation settlement	438					2	436
Commitment to deliver common shares pursuant to litigation settlement to additional paid-in capital	6,056						6,056
Reclassification adjustment for gains (losses) included in net loss	(48)									(48)
Issuance of common shares under Employee Stock Purchase Plan (in shares)	422,260					211,000
Issuance of common shares under Employee Stock Purchase Plan	862					2	860
Unrealized gain/(loss) on foreign currency translation	(2)									(2)
Issuance of common shares pursuant to underwritten public offerings (in shares)						81,938,000
Issuance of common shares pursuant to underwritten public offerings	166,864					819	166,045
Stock-based compensation	13,292						13,292
Net loss	(169,366)										(169,366)
Ending Balance at Dec. 31, 2012	$ (110,679)					$ 2,860	$ 1,991,379			$ (6)	$ (2,104,912)
Ending Balance (in shares) at Dec. 31, 2012						286,035,000