Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets related to continuing operations:
Deferred compensation	$ 924	$ 998
Inventory valuation	664	661
Tax loss carryforward	1,587	1,913
Foreign tax credit carryforward		17
R&D tax credit carryforward	1,047	876
Accrued expenses	508	520
Warranty	414	514
Vacation and bonus expense	1,330	1,775
Other	537	342
Less valuation allowances	(415)	(417)
Deferred tax assets related to continuing operations	6,596	7,199
Deferred tax liabilities related to continuing operations:
Accelerated depreciation and amortization	2,676	2,866
Net deferred tax assets related to continuing operations	3,920	4,333
Net deferred tax assets related to discontinued operations	9,214	8,981
Net deferred tax assets	$ 13,134	$ 13,314