Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policy [Line Items]
Beginning Balance	$ 588	$ (6,828)	$ (5,472)
Foreign currency translation	826	7,419	(1,335)
Unrealized gain on investments before reclassification, net of tax	(111)	14	(9)
Reclassification adjustment for net gains realized in net income, net of tax	1,151	(17)	(12)
Ending Balance	2,454	588	(6,828)
Net Unrealized Loss on Marketable Investments [Member]
Summary Of Significant Accounting Policy [Line Items]
Beginning Balance	(1,024)	(1,021)	(1,000)
Unrealized gain on investments before reclassification, net of tax	(111)	14	(9)
Reclassification adjustment for net gains realized in net income, net of tax	1,151	(17)	(12)
Ending Balance	16	(1,024)	(1,021)
Cumulative Translation Adjustment [Member]
Summary Of Significant Accounting Policy [Line Items]
Beginning Balance	1,612	(5,807)	(4,472)
Foreign currency translation	826	7,419	(1,335)
Ending Balance	$ 2,438	$ 1,612	$ (5,807)