Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Y	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Line Items]
Statutory U.S. federal income tax rate	35.00%
Deferred tax assets, valuation allowance	$ 26.5	$ 20.1
State net operating loss carryforwards	51.5
Foreign net operating loss carryforwards	69.5
Net operating loss carryforwards, beginning expiration year	2013
Research and development credit carry forward	18.8	38.2
Research and development credit carry forward, beginning expiration year	2013
Research and development credit carry forward, ending expiration year	2027
Earnings from foreign subsidiaries that residual U.S. income taxes is not provided	575
Cumulative unrealized tax deductions related to stock option exercises and vested restricted shares	19.9
Realized tax deductions related to stock option exercises and vested restricted shares	7.0
Gross uncertain tax position	34.6	21.7	21.5	18.5
Liability for unrecognized tax benefits that would affect effective tax rate, if recognized	32.1
Number of tax years the company is currently open to audit by tax authorities	6
Minimum
Income Taxes [Line Items]
Liability for unrecognized tax benefits for interest and penalties	$ 1.0	$ 1.0