CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue:
Collaboration revenue	$ 15,855	$ 12,500
Total revenue	15,855	12,500
Operating expenses:
Research and development	5,255,065	7,994,472
General and administrative	3,777,546	3,745,262
Total operating expenses	9,032,611	11,739,734
Loss from operations	(9,016,756)	(11,727,234)
Other income (expense), net:
Interest income, net	412,897	235,451
Other income (expense), net	1,213	3,198
Net loss	$ (8,602,646)	$ (11,488,585)
Net loss per share -basic and diluted (in dollars per share)	$ (0.16)	$ (0.27)
Items included in other comprehensive income (loss):
Unrealized gain (loss) and amounts reclassified to net loss on available-for-sale securities	$ (14,710)	$ (12,681)
Other comprehensive income (loss)	(14,710)	(12,681)
Comprehensive loss	$ (8,617,356)	$ (11,501,266)
Weighted-average number of common shares used in net loss per share calculation - basic and diluted (in shares)	55,000,743	42,434,709