Accrued Expenses (Details) - USD ($)	Jun. 30, 2018		Dec. 31, 2017
Accrued Expenses [Abstract]
Accrued research and development costs	$ 5,515,479	[1]	$ 2,857,025
Accrued professional fees	201,675		267,646
Accrued compensation	67,834		1,886,638
Accrued other	209,923		385,896
Deferred rent	29,616		25,000
Total	6,024,527		$ 5,422,205
Accrued close down NEWTON 2 trial costs	3,000,000
Accrued CMO milestone payments	$ 2,500,000

[1] Balance as of June 30, 2018 includes estimated close down NEWTON 2 trial costs of $3.0 million and CMO milestone payments of $2.5 million.