Commitments and Contingencies (Letters of Credit and Guarantees) - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Commitments And Contingencies [Line Items]
Letters of credit outstanding	$ 2.3
License bonds outstanding amount	2.5	$ 2.3
Letters of Credit [Member]
Commitments And Contingencies [Line Items]
Letters of credit outstanding	$ 2.3	$ 2.3