Principal Maturities of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Debt Instrument [Line Items]
Debt maturing in 2013	$ 17,218
Debt maturing in 2014	12,767
Debt maturing in 2015	9,934
Debt maturing in 2016	17,033
Total debt	56,952
US Term Note
Debt Instrument [Line Items]
Debt maturing in 2013	4,812
Debt maturing in 2014	5,687
Debt maturing in 2015	6,563
Debt maturing in 2016	12,250
Total debt	29,312
Europe Term Note
Debt Instrument [Line Items]
Debt maturing in 2014	542
Debt maturing in 2015	558
Debt maturing in 2016	3,376
Total debt	4,476
W.E.T. Term Note
Debt Instrument [Line Items]
Debt maturing in 2013	8,094
Debt maturing in 2014	6,538
Debt maturing in 2015	2,813
Debt maturing in 2016	1,407
Total debt	18,852
Bank Of China
Debt Instrument [Line Items]
Debt maturing in 2013	3,172
Total debt	3,172
Capital Lease [Member]
Debt Instrument [Line Items]
Debt maturing in 2013	1,140
Total debt	$ 1,140