Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued license fees	$ 795,000	$ 817,578
Accrued pre-commercial costs	322,418	341,159
Accrued consulting	210,515	102,156
Accrued contract research	187,915	99,140
Accrued miscellaneous expenses	157,861	73,348
Accrued contract manufacturing	90,054	218,108
Accrued audit and tax	88,540	111,250
Accrued legal	18,544	174,592
Accrued expenses	$ 1,870,847	$ 1,937,331