Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Value of outstanding derivative securities that permit the holder the right to purchase securities (usually equity) from the issuer at a specified price.

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Derivative and Other Financial Instruments and Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis Based on Fair Value Hierarchy (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring Basis
Derivative assets	$ 0.6
Derivative liabilities	(0.4)
Common stock warrant liability, estimated fair value	(4.4)	$ (6.9)	$ (5.6)
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring Basis
Net derivative assets (liabilities)	0.2
Fair Value, Recurring \| Level 2
Fair Value Assets And Liabilities Measured On Recurring Basis
Derivative assets	0.6
Derivative liabilities	(0.4)
Fair Value, Recurring \| Level 3
Fair Value Assets And Liabilities Measured On Recurring Basis
Common stock warrant liability, estimated fair value	$ (4.4)