Income Taxes - Carryforwards and Limitations (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Income taxes | ||
| Unrecognized tax benefits, if recognized, would affect its effective income tax rate | $ 0.0 | $ 0.0 |
| Unrecognized tax benefits, income tax penalties and interest accrued | $ 0.0 | |
| Minimum [Member] | ||
| Income taxes | ||
| Percentage of change in ownership | 50.00% | |
| State and Local Jurisdiction [Member] | ||
| Income taxes | ||
| Net operating loss carryforwards amount | $ 348.7 | 329.1 |
| Foreign Tax Jurisdiction [Member] | ||
| Income taxes | ||
| Net operating loss carryforwards amount | 0.2 | 0.2 |
| Internal Revenue Service (IRS) [Member] | ||
| Income taxes | ||
| Net operating loss carryforwards amount | $ 218.9 | $ 207.9 |