Stock-Based Compensation and Employee Benefit Plan - Employee Stock Purchase Plan (Details) - 2018 ESPP - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock ownership plan (ESOP), compensation expense	$ 1.8	$ 2.4	$ 4.7	$ 5.2
Share-based compensation arrangement by share-based payment award, shares issued in period			992,846
Number of additional shares authorized (in shares)			1,494,819
Number of common stock reserved for issuance (in shares)	3,532,380		3,532,380

The amount of plan compensation cost recognized during the period.

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