Accrued Expenses (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Accrued Expenses
Deferred offering costs	$ 691,564	$ 1,080,199
Grants payable		400,000
Accrued research and development	380,765
Other	190,397	231,274
Total accrued expenses	$ 1,262,726	$ 1,711,473