401 (K) Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Employer discretionary contribution amount	$ 2.4	$ 1.9	$ 1.6
Minimum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution as a percentage of employees' gross pay	1.00%
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution as a percentage of employees' gross pay	4.00%