Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on available-for-sale marketable securities, Before income tax	$ (163)
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on available-for-sale marketable securities, provision for income taxes
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on available-for-sale marketable securities	(163)	(71)
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges, Before income tax	(141)
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges, Provision for income taxes
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges	(141)	39
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on components of defined benefit plans, Before income tax	3
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on components of defined benefit plans, Provision for income tax
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on components of defined benefit plans	3
Amounts reclassified from accumulated other comprehensive income, Total	(301)
Research and Development
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges, Before income tax	(111)
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on components of defined benefit plans, Before income tax	2
Sales and Marketing Expense
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges, Before income tax	(11)
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on components of defined benefit plans, Before income tax	1
General and Administrative Expense
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Amounts reclassified from accumulated other comprehensive income, Gains (losses) on Cash Flow Hedges, Before income tax	$ (19)