Income Taxes - Net operating loss carryforwards and Tax Act (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net operating loss carryforwards
Net operating loss carryforwards, which will expire if not utilized	$ 99.7
Tax at statutory federal rate	21.00%	21.00%
Federal
Net operating loss carryforwards
Net operating loss carryforwards	$ 140.5
Net operating loss carryforwards, which will carryover indefinitely	40.8
State
Net operating loss carryforwards
Net operating loss carryforwards	54.1
Net operating loss carryforwards, which will expire if not utilized	51.5
Net operating loss carryforwards, which will carryover indefinitely	$ 2.6