Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue	$ 101,000	$ 314,000	$ 205,000	$ 336,000
Operating expenses
Research and development	1,888,000	3,595,000	2,899,000	4,236,000
General and administrative	1,961,000	2,843,000	3,588,000	3,557,000
Total operating expenses	3,849,000	6,438,000	6,487,000	7,793,000
Loss from operations	(3,748,000)	(6,124,000)	(6,282,000)	(7,457,000)
Other income (expense)
Gain (loss) on derivative liabilities	17,621,000	(6,057,000)	8,848,000	(5,970,000)
Amortization of note discount	0	(2,334,000)	0	(2,637,000)
Interest expense, net	0	(128,000)	0	(224,000)
Other income (expense), net	17,621,000	(8,519,000)	8,848,000	(8,831,000)
Net loss	13,873,000	(14,643,000)	2,566,000	(16,288,000)
Accretion of Series B redeemable convertible preferred stock	(318,000)	(103,000)	(632,000)	(103,000)
Net loss attributable to common stockholders	$ 13,555,000	$ (14,746,000)	$ 1,934,000	$ (16,391,000)
Per share information:
Net income (loss) per share - basic (in dollars per share)	$ 0.07	$ (0.16)	$ 0.01	$ (0.21)
Net income (loss) per share - diluted (in dollars per share)	$ 0.04	$ (0.16)	$ 0.01	$ (0.21)
Weighted average number of shares of common stock outstanding - basic (in shares)	183,590,053	90,645,074	183,065,721	78,842,512
Weighted average number of shares of common stock outstanding - diluted (in shares)	324,880,957	90,645,074	325,709,071	78,842,512