Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued pre-commercial costs	$ 1,045,962	$ 85,000
Accrued payroll and payroll taxes	1,035,482	1,302,728
Accrued contract manufacturing	385,000	1,079,314
Accrued miscellaneous expenses	281,246	119,861
Accrued consulting	230,000	49,940
Accrued legal	87,622	111,543
Accrued accounting, audit, and tax fees	87,000	102,000
Accrued license fees	19,671	1,567,368
Accrued contract research and regulatory consulting		128,678
Total accrued expenses	$ 3,171,983	$ 4,546,432