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Summary of Significant Accounting Policies - Research and Development (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accounting Policies [Abstract]      
Research and Development Expense $ 14.1 $ 17.8 $ 22.7
Customer funded research and development costs $ 0.7 $ 2.4 $ 2.2