Fair Value of Outstanding Derivative Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets	$ 240	$ 216
Derivative liabilities	196	112
Derivatives not qualified as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities	178	112
Foreign exchange option contracts | Derivatives designated as cash flow hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets	166	158
Foreign exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities	18
Foreign exchange forward contracts | Derivatives designated as cash flow hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets	$ 74	$ 58