Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Intangible Assets (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2018
Dec. 31, 2017
Finite-Lived Intangible Assets, Net [Abstract]    
Accumulated amortization $ 1.8 $ 1.4
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]    
2019 0.4  
2020 0.2  
2021 0.1  
2022 0.1  
2023 0.1  
Thereafter 0.7  
Net amortization expense $ 1.6