STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Licensing revenue	$ 100,000	$ 100,000	$ 300,000
Expenses:
Research and development	43,395,574	36,677,706	17,500,469
General and administrative	19,664,904	12,845,231	10,273,576
Depreciation and amortization	317,649	182,927	120,399
Total expenses	63,378,127	49,705,864	27,894,444
Loss before other income (loss)	(63,278,127)	(49,605,864)	(27,594,444)
Other income (loss):
Interest income	233,958	305,331	137,676
Other income, net	20,151	132,114	183,025
Gain (loss) on warrant liability	4,437,628	19,051,239	(20,210,094)
Loss before provision for income taxes	(58,586,390)	(30,117,180)	(47,483,837)
Provision for income taxes	(800)	(800)	(1,600)
Net loss	$ (58,587,190)	$ (30,117,980)	$ (47,485,437)
Basic and diluted loss per share (in dollars per share)	$ (0.97)	$ (0.55)	$ (1.44)
Basic and diluted weighted average shares outstanding (in shares)	60,483,151	54,371,151	32,891,202