Accrued Expenses - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Accrued Liabilities And Other Liabilities [Abstract]
Accrued professional services	$ 398,754	$ 552,619
Accrued payroll and employee benefits	954,658	1,257,191
Accrued interest	3,441	1,192
Accrued research and development	682,463	2,076,704
Lease obligation, current portion	252,755
Deferred rent, current portion		175,490
Deferred revenue	19,753	19,753
Total accrued expenses	$ 2,311,824	$ 4,082,949