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Intangible Assets - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]          
Goodwill $ 0.6   $ 0.6   $ 0.6
Amortization expense $ 1.6 $ 1.2 $ 4.6 $ 4.2