Income Taxes - Operating loss carryforwards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating loss carryforwards
Percentage of valuation allowance equal to deferred tax asset	100.00%
Operating loss carryforward available for immediate use	$ 25,590,114
Research and development tax credit
Operating loss carryforwards
Research and development tax credit carryforwards	13,733,227	$ 262,831
Federal
Operating loss carryforwards
Net operating loss carryforwards	$ 34,551,469	$ 16,525,413