Pro Forma Adjustments Affecting Net Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Depreciation and amortization of purchased assets, pre-tax	$ (6.3)	$ (12.9)
Acquisition-related expenses, pre-tax	4.8	1.2
Restructuring and impairment charges, pre-tax	2.7	(2.2)
Inventory fair value adjustments, pre-tax	0.3	(0.2)
Other pro forma adjustments, pre-tax	0.1	(14.3)
Income taxes	$ (3.6)	$ 12.4