Research and Development Prepaid Expenses and Accrued Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid research and development expenditures	$ 8.5	$ 7.7
Accrued research and development expenditure	1.5	$ 3.2
Result in total research and development expense of 5% increase in completion	1.9
Result in total research and development expense of 5% decrease in completion	$ 2.3