Commitments and Contingencies - Additional Information (Detail) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2018 patent	Dec. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Rent expense			$ 7.5	$ 5.7	$ 5.0
Purchase obligation, due in next year		$ 42.5	42.5
Purchase obligation, due in second year		23.6	23.6
Purchase obligation, due in third year		25.8	25.8
Purchase obligation, due in fourth year		0.2	0.2
Purchase obligation, due in fifth year		0.0	0.0
Purchase obligation, due after fifth year		0.1	0.1
Settlement amount		0.6
Patents allegedly infringed, number | patent	7
Letter of Credit [Member]
Commitments And Contingencies Disclosure [Line Items]
Long-term line of credit		$ 8.2	$ 8.2