Segment and Enterprise-Wide Disclosures - Net Sales to Unaffiliated Customers by Geography (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Net sales	$ 15,300	$ 13,645	$ 46,633	$ 41,934
United States [Member]
Segment Reporting Information [Line Items]
Net sales	9,506	8,811	28,820	27,191
Germany [Member]
Segment Reporting Information [Line Items]
Net sales	1,805	1,419	5,166	4,149
Japan [Member]
Segment Reporting Information [Line Items]
Net sales	609	667	1,779	1,955
Other countries [Member]
Segment Reporting Information [Line Items]
Net sales	$ 3,380	$ 2,748	$ 10,868	$ 8,639