Segment Information and Foreign Operations - Segment and Geographical Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Dec. 31, 2016 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	$ 23,557	$ 20,495	$ 44,173	$ 39,208
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	27,945		27,945		$ 27,805
Reportable Geographical Components | Europe
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	5,848	4,573	11,446	8,951
Reportable Geographical Components | China
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	6,324	4,183	10,746	7,275
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	26,987		26,987		27,487
Reportable Geographical Components | Taiwan
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	4,195	4,649	7,513	8,784
Reportable Geographical Components | Japan
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	2,862	2,695	6,002	4,597
Reportable Geographical Components | Asia Pacific (excluding China, Taiwan, and Japan)
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	2,645	2,402	4,716	5,152
Reportable Geographical Components | North America
Net revenues reported for products shipped to customers in corresponding geographic region [Abstract]
Revenue	1,683	$ 1,993	3,750	$ 4,449
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	$ 958		$ 958		$ 318