Reconciliation between Income Taxes Computed at Federal Statutory Rate and Provision (Benefit) for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal income tax provision computed at statutory rates	$ 4,269	$ 2,407	$ 2,281
Difference in foreign tax rate	(405)	174	(141)
State income taxes, net of federal benefit	142	140	27
Stock-based compensation	142	966	96
Research and development tax credits	(33)	(256)	56
Expiration of tax credits	236	167	200
Foreign tax credits	(2,527)	(47)	(136)
Foreign dividend	1,281
Change in valuation allowance	(158)	(9,656)	(1,877)
Unrecognized tax benefits	8	9	9
Foreign earnings not permanently reinvested		(207)	(58)
Domestic production deduction	(251)
Other	30	(34)	252
Income tax (benefit) expense	$ 2,734	$ (6,337)	$ 709