Segments, Concentrations and Geographic Information - Net Sales to Third Parties by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 442.9	$ 228.5	$ 1,392.2	$ 706.2
North America (primarily U.S.) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	251.5	115.1	794.3	359.9
Europe Excluding Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	72.1	43.5	233.8	130.1
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	54.9	46.6	173.9	144.7
Asia And Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 64.4	$ 23.3	$ 190.2	$ 71.5