Income Taxes (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	$ 0	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		124,700,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		115,300,000
R&D credit
Operating Loss Carryforwards [Line Items]
Credit carryforwards		$ 1,900,000