Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating expenses:
Research and development expenses	$ 12,742,085	$ 7,589,496
General and administrative expenses	4,681,516	4,201,842
Impairment charges	2,672,581	0
Total operating expenses	20,096,182	11,791,338
Loss from operations	(20,096,182)	(11,791,338)
Other income (expense):
Interest income	246,639	96,259
Interest expense	(990,560)	(475,141)
Net loss	(20,840,103)	(12,170,220)
Comprehensive loss	$ (20,840,103)	$ (12,170,220)
Loss per share basic and diluted (in dollars per share)	$ (0.67)	$ (0.42)
Weighted average common shares outstanding basic and diluted (in shares)	30,965,874	28,998,616