Consolidated Statements of Stockholders' Equity (Deficit) (USD $) In Thousands, except Share data	Total	Partnership Units	Common Stock	Additional Paid-In Capital	Deficit Accumulated During the Development Stage
BALANCE at Jul. 21, 1980
BALANCE (in shares) at Jul. 21, 1980
Issuance of partnership units, warrants and common stock, shares		602,000	1,379,000
Issuance of partnership units, warrants and common stock	33,734			33,734
Compensation expense related to issuance of warrants for common stock and partnership units	537			537
Exercise of warrants for partnership units and common stock, shares		7,000	375,000
Exercise of warrants for partnership units and common stock	4,152			4,152
Exercise of options for common stock	6,221			6,221
Exercise of options for common stock, shares			467,000
Exercise of warrants for common stock	549			549
Exercise of warrants for common stock, shares			51,000
Issuance of common stock for ESPP	2,417			2,417
Issuance of common stock for ESPP, shares			163,000
Issuance of common stock and warrants for cash and securities, net of offering costs, shares			14,400,000
Issuance of common stock and warrants for cash and securities, net of offering costs	207,322		2	207,320
Issuance of common stock and warrants for the acquisition of business interests	25,559			25,559
Issuance of common stock and warrants for the acquisition of business interests, shares			1,324,000
Issuance of common stock and warrants to vendors	3,297			3,297
Issuance of common stock and warrants to vendors, shares			143,000
Stock-based compensation, net of cancellations of restricted stock	21,419			21,419
Stock-based compensation, net of cancellations of restricted stock, shares			160,000
Conversion of debt into common stock and partnership units	88			88
Conversion of debt into common stock and partnership units, shares		2,000	2,000
Issuance of common stock in exchange for partnership units, shares		(302,000)	272,000
Withdrawal of partnership net assets upon conveyance of technology	(177)			(177)
Withdrawal of partnership net assets upon conveyance of technology, shares		(309,000)
Common stock subject to rescission, net	(289)			(289)
Common stock subject to rescission net, shares			(11,000)
Net loss	(307,646)				(307,646)
BALANCE at Dec. 31, 2010	(2,817)		2	304,827	(307,646)
BALANCE (in shares) at Dec. 31, 2010			18,725,000
Exercise of options for common stock	166			166
Exercise of options for common stock, shares	25,291		30,000
Exercise of warrants for common stock	759			759
Exercise of warrants for common stock, shares			35,000
Issuance of common stock for cash, net of offering costs	32,098			32,098
Issuance of common stock for cash, net of offering costs, shares			3,834,000
Stock-based compensation, net of cancellations of restricted stock	3,129			3,129
Stock-based compensation, net of cancellations of restricted stock, shares
Net loss	(2,318)				(2,318)
BALANCE at Dec. 31, 2011	31,017		2	340,979	(309,964)
BALANCE (in shares) at Dec. 31, 2011			22,624,000
Exercise of options for common stock	3,780			3,780
Exercise of options for common stock, shares	371,353		372,000
Exercise of warrants for common stock	52,742			52,742
Exercise of warrants for common stock, shares			1,770,000
Issuance of common stock for cash, net of offering costs	154,349		1	154,348
Issuance of common stock for cash, net of offering costs, shares			6,934,000
Stock-based compensation, net of cancellations of restricted stock	3,078			3,078
Stock-based compensation, net of cancellations of restricted stock, shares			4,000
Net loss	(121,287)				(121,287)
BALANCE at Dec. 31, 2012	123,679		3	554,927	(431,251)
BALANCE (in shares) at Dec. 31, 2012	31,703,817		31,704,000
Exercise of options for common stock	2,725			2,725
Exercise of options for common stock, shares	241,056		241,000
Exercise of warrants for common stock	96,768			96,768
Exercise of warrants for common stock, shares			2,336,000
Restricted stock unit issuance
Restricted stock unit issuance, shares			31,000
Shares withheld for taxes	(226)			(226)
Shares withheld for taxes, shares			(7,000)
Restricted stock awards granted
Restricted stock awards granted, shares			6,000
Issuance of common stock for cash, net of offering costs	125,104		1	125,103
Issuance of common stock for cash, net of offering costs, shares			3,441,000
Stock-based compensation, net of cancellations of restricted stock	11,127			11,127
Stock-based compensation, net of cancellations of restricted stock, shares
Net loss	(111,985)				(111,985)
BALANCE at Dec. 31, 2013	$ 247,192		$ 4	$ 790,424	$ (543,236)
BALANCE (in shares) at Dec. 31, 2013	37,751,920		37,752,000