Contingencies and Commitments - Additional Information (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Maximum [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	$ 7.0
French Research and Development Tax Credit, Denied by Tax Authority [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	0.8
French Research and Development Tax Credit, Claimed Credits with Risk of Denial by Tax Authority [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	$ 3.8