Segment Information - Summary of Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	$ 7,106	$ 14,469	$ 16,016	$ 28,737
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,813	7,420	5,163	13,870
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,261	2,153	1,986	4,049
Taiwan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,211	2,269	2,913	6,033
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,131	238	1,641	271
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	998	1,590	2,521	2,960
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	291	390	614	686
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	200	145	415	145
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	127	157	243	425
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	$ 74	$ 107	$ 520	$ 298