Maturities of Marketable Securities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Investments [Line Items]
Less than 1 year	$ 4,587	$ 20,658
Due in 1 to 2 years	2,014	2,008
Due in 2 to 5 years
Due after 5 years	1,700	1,801
Total	$ 8,301	$ 24,467