Reconciliation of Federal Statutory Tax Rate and Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Effective Tax Rates Line Items
Federal statutory tax rate	35.00%	35.00%	35.00%
Research and development tax credit	(3.50%)
State government grants, net of federal tax impact	(0.10%)	(0.30%)	(0.10%)
Domestic manufacturing deduction	2.70%		(2.80%)
State income taxes, net of federal impact	(4.00%)	1.60%	1.60%
Other, net	0.10%	0.10%	0.30%
Effective income tax rate	30.20%	36.40%	34.00%