CONDENSED STATEMENTS OF OPERATIONS (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue:
License revenue	$ 0	$ 0	$ 0	$ 0
Expenses:
Research and development	10,008,304	10,427,877	22,573,181	17,415,725
General and administrative	4,191,769	2,909,127	7,322,001	6,040,201
Total expenses	14,200,073	13,337,004	29,895,182	23,455,926
Loss before other income (loss)	(14,200,073)	(13,337,004)	(29,895,182)	(23,455,926)
Other income (loss):
Interest income	46,455	89,377	103,029	160,015
Other income (loss), net	30,660	(3,243)	15,940	6,655
Gain (loss) on warrant derivative liability	2,435,865	(2,468,603)	564,570	12,234,301
Net loss	$ (11,687,093)	$ (15,719,473)	$ (29,211,643)	$ (11,054,955)
Basic and diluted net loss per share (in dollars per share)	$ (0.21)	$ (0.28)	$ (0.52)	$ (0.21)
Basic and diluted weighted-average shares outstanding (in shares)	55,726,432	55,676,766	55,724,581	53,010,556