Accrued Expenses (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Accrued Expenses
Payroll and related costs	$ 33,393	$ 1,399,264
Research and development related costs	2,410,956	1,445,369
Professional fees	551,391	411,096
Interest	155,556	167,111
Other	31,119	304,944
Accrued expenses	$ 3,182,415	$ 3,727,784