Statements Of Shareholders' Equity (Deficit) And Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	Common Stock [Member] USD ($)	Additional Paid-In Capital [Member] USD ($)	Accumulated Other Comprehensive Income (Loss) [Member] USD ($)	Deficit Accumulated During The Development Stage [Member] USD ($)	Partnership Units [Member]	Total USD ($)
BALANCE AT BEGINNING at Jul. 21, 1980
Issuance of partnership units, warrants and common stock	$ 1	$ 33,733				$ 33,734
Issuance of partnership units, warrants and common stock, shares	8,273				3,615
Compensation expense related to issuance of warrants for common stock and partnership units		537				537
Exercise of warrants for partnership units and common stock		4,152				4,152
Exercise of warrants for partnership units and common stock, shares	2,248				42
Exercise of options for common stock		4,133				4,133
Exercise of options for common stock, shares	1,036
Issuance of common stock for ESPP		2,332				2,332
Issuance of common stock for ESPP, shares	854
Issuance of common stock and warrants for cash and securities, net of offering costs	5	176,795				176,800
Issuance of common stock and warrants for cash and securities, net of offering costs, shares	47,882
Issuance of common stock and warrants for the acquisition of business interests	1	25,558				25,559
Issuance of common stock and warrants for the acquisition of business interests, shares	7,944
Issuance of common stock and warrants to vendors		3,297				3,297
Issuance of common stock and warrants to vendors, shares	860
Compensation expense related to issuance of options for common stock		7,155				7,155
Stock-based compensation		8,721				8,721
Stock-based compensation, shares	426
Conversion of debt into common stock and partnership units		88				88
Conversion of debt into common stock and partnership units, shares	10				9
Issuance of common stock in exchange for partnership units, shares	1,633				(1,810)
Withdrawal of partnership net assets upon conveyance of technology		(177)				(177)
Withdrawal of partnership net assets upon conveyance of technology, shares					(1,856)
Common stock subject to rescission, net		(289)				(289)
Common stock subject to rescission net, shares	(64)
Comprehensive income (loss):
Write-down of short-term securities-available-for-sale			17,001			17,001
Realized gain on sale of short-term securities-available-for-sale			(3,766)			(3,766)
Unrealized loss on short-term securities-available-for-sale			(13,235)			(13,235)
Net loss				(250,310)		(250,310)
Comprehensive loss						(250,310)
BALANCE AT ENDING at Dec. 31, 2008	7	266,035		(250,310)		15,732
BALANCE AT ENDING, SHARES at Dec. 31, 2008	71,102
Exercise of options for common stock		76				76
Exercise of options for common stock, shares	62
Issuance of common stock for ESPP		85				85
Issuance of common stock for ESPP, shares	124
Issuance of common stock for cash and securities, net of offering costs	4	30,518				30,522
Issuance of common stock for cash and securities, net of offering costs, shares	38,520
Stock-based compensation		2,171				2,171
Stock-based compensation, shares	261
Compensation expense on issuance of restricted stock		203				203
Compensation expense on issuance of restricted stock, shares	427
Comprehensive income (loss):
Net loss				(25,159)		(25,159)
Comprehensive loss						(25,159)
BALANCE AT ENDING at Dec. 31, 2009	11	299,088		(275,469)		23,630
BALANCE AT ENDING, SHARES at Dec. 31, 2009	110,496
Exercise of options for common stock		2,012				2,012
Exercise of options for common stock, shares	1,702
Stock-based compensation		3,105				3,105
Compensation expense on issuance of restricted stock		64				64
Compensation expense on issuance of restricted stock, shares	(154)
Exercise of warrants for common stock		549				549
Exercise of warrants for common stock, shares	308
Comprehensive income (loss):
Net loss				(32,177)		(32,177)
Comprehensive loss						(32,177)
BALANCE AT ENDING at Dec. 31, 2010	11	304,818		(307,646)		(2,817)
BALANCE AT ENDING, SHARES at Dec. 31, 2010	112,352
Exercise of options for common stock		166				166
Exercise of options for common stock, shares	182
Issuance of common stock for cash, net of offering costs	2	32,096				32,098
Issuance of common stock for cash, net of offering costs, shares	23,000
Stock-based compensation		3,096				3,096
Compensation expense on issuance of restricted stock		33				33
Exercise of warrants for common stock		759				759
Exercise of warrants for common stock, shares	209
Comprehensive income (loss):
Net loss				(2,318)		(2,318)
Comprehensive loss						(2,318)
BALANCE AT ENDING at Dec. 31, 2011	$ 13	$ 340,968		$ (309,964)		$ 31,017
BALANCE AT ENDING, SHARES at Dec. 31, 2011	135,743