Reconciliation of Tax Contingencies (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Schedule of Unrecognized Tax Benefits [Line Items]      
Gross tax contingencies, beginning balance $ 534 $ 250 $ 305
Gross increases to tax positions associated with prior periods     28
Gross increases to current period tax positions 183 284  
Gross decreases to tax positions associated with prior periods     (83)
Settlements 0 0 0
Lapse of statute of limitations 0 0 0
Gross tax contingencies, ending balance $ 717 $ 534 $ 250