2013 Restructuring - Reconciliation of Beginning and Ending Liability Balances by Expense Type (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Costs charged to expense	$ 46	$ 515
Severance Expense [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	32
Costs charged to expense		419
Costs paid or otherwise settled	(32)	(387)
Ending Balance		32
Other Expense [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	14
Costs charged to expense	46	96
Costs paid or otherwise settled	(14)	(82)
Ending Balance		$ 14