Accrued Expenses (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Accrued Expenses
Research and development	$ 1,976,412	$ 1,693,748
Accrued compensation	159,174	539,290
Other	399,538	587,339
Accrued expenses	$ 2,535,124	$ 2,820,377