Supplementary Balance Sheet Information - Accrued Expenses (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued compensation	$ 2,203,876	$ 896,404
Accrued research agreements	736,199	386,267
Accrued professional fees	421,314	0
Other accrued liabilities	659,976	621,126
Total accrued liabilities	$ 4,021,365	$ 1,903,797