Consolidated Statements of Operations - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Collaboration revenues	$ 3,811,519	$ 2,979,576
Operating expenses:
Research and development	23,809,749	32,763,178
General and administrative	15,882,033	21,563,573
Operating expenses total	39,691,782	54,326,751
Loss from operations	(35,880,263)	(51,347,175)
Interest expense, net	5,625,833	1,851,814
Change in fair value of warrant liability	(3,158,469)
Loss before income taxes	(38,347,627)	(53,198,989)
Income tax expense	501,500	103,000
Net loss	(38,849,127)	(53,301,989)
Recognition of beneficial conversion feature upon issuance of Series A convertible preferred stock	(1,176,743)
Accretion of redeemable preferred stock and noncontrolling interests		(2,463,160)
Deemed dividend upon issuance of warrants to common stockholders		(7,373,820)
Net loss attributable to common stockholders	$ (40,025,870)	$ (63,138,969)
Per share information:
Net loss per share of common stock, basic (in dollars per share)	$ (1.67)	$ (3.67)
Net loss per share of common stock, diluted (in dollars per share)	$ (1.80)	$ (3.67)
Weighted average shares outstanding, basic (in shares)	24,022,371	17,212,983
Weighted average shares outstanding, diluted (in shares)	24,041,789	17,212,983