Restructuring Costs (Details) - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Restructuring Costs
Reduction in workforce (as a percent)	40.00%
Restructuring expense				$ 2,300,000
EC1456 Phase 1 Trial Termination Accrual
Restructuring Costs
Accrual balance		$ 0	$ 0		$ 106,900
Adjustments to accrual balance		0	0
Amounts paid during the period		$ 14,800	$ 106,900
General and Administrative Expense
Restructuring Costs
Employee termination benefits				100,000
Research and Development Expense.
Restructuring Costs
Employee termination benefits				900,000
Remaining EC1456 phase 1b trial expenses, including site close-out expenses				900,000
Other restructuring expenses				300,000
Fixed asset impairment				$ 100,000