401(k) Savings Plan - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Percent match	50.00%
Contributions to plan	$ 500,000	$ 0
Maximum
Defined Contribution Plan Disclosure [Line Items]
Maximum percent for match	6.00%