Cash, Cash Equivalents and Investments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Security	Dec. 31, 2012	Dec. 31, 2011
Cash And Cash Equivalents [Abstract]
Liquid investments with maturities	3 months
Unrealized gain, net of taxes	$ 10,000	$ 14,000	$ 12,000
Realized gains or losses	23,000	0	0
Number of securities in unrealized loss position	2
Maximum duration of security	20 months
Unrealized loss available for sale securities, less than 12 months	1,000
Unrealized loss available for sale securities fair value, less than 12 months	$ 1,800,000
Municipal bonds maturity Start - date	Jun. 30, 2014
Municipal bonds maturity End - date	Dec. 31, 2015