Income Taxes - Tax Credit Carryforwards (Details) $ in Millions |
Dec. 31, 2019
USD ($)
|
|---|---|
| Tax Credit Carryforward [Line Items] | |
| Taxable income required for full realization of deferred tax assets | $ 650.1 |
| Federal | Research and development tax credit carryforward | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryforward | 15.7 |
| Federal | Tax credit that can be carried forward indefinitely | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryforward | 194.2 |
| State | Research and development tax credit carryforward | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryforward | $ 13.0 |