Segment Information and Foreign Operations - Segment and Geographical Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments | segment			1
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	$ 21,872	$ 18,371	$ 61,080	$ 59,445
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	29,385		29,385		$ 31,422
Reportable Geographical Components | Europe
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	4,995	4,385	13,946	14,992
Reportable Geographical Components | China
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	4,766	3,296	12,041	10,154
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	28,767		28,767		30,880
Reportable Geographical Components | Japan
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	3,499	1,939	8,096	7,176
Reportable Geographical Components | Asia Pacific (excluding China, Taiwan, and Japan)
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	3,239	2,750	8,391	8,277
Reportable Geographical Components | Taiwan
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	2,995	4,131	11,779	10,654
Reportable Geographical Components | North America
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	2,378	$ 1,870	6,827	$ 8,192
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	$ 618		$ 618		$ 542