Stockholders' Equity - Share-Based Compensation Expense (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]      
Total stock-based compensation $ 1,424 $ 1,302 $ 1,253
Stock Option Awards [Member]      
Schedule of Trading Securities and Other Trading Assets [Line Items]      
Total stock-based compensation 992 917 789
Restricted Stock Units [Member]      
Schedule of Trading Securities and Other Trading Assets [Line Items]      
Total stock-based compensation $ 432 $ 385 $ 464