Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating expenses:
Research and development expenses	$ 6,913,171	$ 6,724,503	$ 23,477,971	$ 18,046,572
General and administrative expenses	3,990,283	3,552,289	12,365,509	10,526,775
Total operating expenses	10,903,454	10,276,792	35,843,480	28,573,347
Loss from operations	(10,903,454)	(10,276,792)	(35,843,480)	(28,573,347)
Other income (expense):
Other expense	0	(163,463)	0	(163,463)
Interest income	214,064	56,082	479,297	148,272
Interest expense	(592,089)	(375,089)	(1,591,998)	(717,263)
Net loss	(11,281,479)	(10,759,262)	(36,956,181)	(29,305,801)
Comprehensive loss	$ (11,281,479)	$ (10,759,262)	$ (36,956,181)	$ (29,305,801)
Loss per share basic and diluted (in dollars per share)	$ (0.37)	$ (0.37)	$ (1.23)	$ (1.02)
Weighted average common shares outstanding basic and diluted (in shares)	30,852,514	28,896,941	30,091,640	28,848,842