Summary of significant accounting policies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014 tradename unit	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]
Number of reporting units	5
Number of reporting units, two-step quantitative impairment test	3
Number of trade names	2
Asset Impairment Charges			$ 10,841,000
Weighted average amortization period of intangible assets, in years		13 years
Reserve for returns and allowances		4,100,000	3,300,000
Reserve for estimated rebates		10,400,000	7,800,000
In-process Research and Development Asset
Summary Of Significant Accounting Policies [Line Items]
Asset Impairment Charges			7,400,000
Minimum | Intellectual property
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		3 years
Minimum | Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		5 years
Minimum | Distribution rights
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		3 years
Minimum | Trade Names
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		1 year
Maximum | Intellectual property
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		20 years
Maximum | Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		30 years
Maximum | Distribution rights
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		22 years
Maximum | Trade Names
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		30 years
Land Improvements
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		5 years
Building
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		30 years
Machinery and Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		3 years
Machinery and Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		10 years
Computer Equipment and Software | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		3 years
Computer Equipment and Software | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		10 years
Previously Reported
Summary Of Significant Accounting Policies [Line Items]
Payments related to tax withholding for share-based compensation			$ 2,700,000	$ 1,600,000