Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development expenses	$ 7,589,496	$ 5,346,763
General and administrative expenses	4,201,842	3,685,597
Total operating expenses	11,791,338	9,032,360
Loss from operations	(11,791,338)	(9,032,360)
Other income (expense):
Interest income	96,259	42,814
Interest expense	(475,141)	(180,864)
Net loss	(12,170,220)	(9,170,410)
Comprehensive loss	$ (12,170,220)	$ (9,170,410)
Loss per share basic and diluted (in dollars per share)	$ (0.42)	$ (0.32)
Weighted average common shares outstanding basic and diluted (in shares)	28,998,616	28,812,907