Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued contract manufacturing	$ 926,000	$ 1,079,314
Accrued pre-commercial costs	502,125	85,000
Accrued consulting	189,214	49,940
Accrued legal	185,652	111,543
Accrued accounting, audit, and tax fees	172,000	102,000
Accrued miscellaneous expenses	150,125	119,861
Accrued payroll and payroll taxes	29,883	1,302,728
Accrued license fees		1,567,368
Accrued contract research and regulatory consulting		128,678
Total accrued expenses	$ 2,154,999	$ 4,546,432