Assets and Liabilities Measured at Fair Value on Recurring Basis Based on Fair Value Hierarchy (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	$ 0.4	$ 0.6
Derivative liabilities as classified in the unaudited condensed consolidated balance sheet	(0.3)	(0.4)
Common stock warrant liability, estimated fair value	(1.9)	(4.4)	$ (7.5)	$ (6.9)
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net derivative assets	0.1	0.2
Fair Value, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	0.4	0.6
Derivative liabilities as classified in the unaudited condensed consolidated balance sheet	(0.3)	(0.4)
Fair Value, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock warrant liability, estimated fair value	$ (1.9)	$ (4.4)