Summary of Significant Accounting Policies - Activity in Allowance for Doubtful Accounts (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Accounting Policies [Abstract]      
Balance, beginning $ 180 $ 109 $ 111
Provision for bad debt 116 100 85
Uncollectible accounts written off 27 29 87
Balance, ending $ 269 $ 180 $ 109