Global Thermoelectric Acquisition - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified			3 Months Ended	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Global Thermoelectric Inc	Sep. 30, 2014 Global Thermoelectric Inc
Business Acquisition [Line Items]
Product revenues			$ 8,532	$ 16,706
Operating Income			639	597
Net assets acquired			31,102	31,102
Cash acquired on acquisition				3,061
Goodwill	30,264	25,809	6,601	6,601
Intangible Assets before Foreign Currency Adjustment			9,871	9,871
Decrease in intangible assets, net, fluctuations in foreign currency exchange rates				120
Amortization expense			$ 667	$ 1,316