Accrued Expenses - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Accrued Liabilities And Other Liabilities [Abstract]
Accrued professional services	$ 472,329	$ 429,467
Accrued payroll and employee benefits	956,584	1,183,130
Accrued interest	10,240	5,047
Accrued research and development	2,343,629	1,966,111
Lease obligation, current portion (see Note 12)	273,276	259,449
Deferred revenue	33,691	61,563
Total accrued expenses	$ 4,089,749	$ 3,904,767