Segment Information - Summary of Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	$ 5,346	$ 8,036	$ 21,362	$ 36,773
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	320	2,851	5,483	16,721
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,267	794	3,253	4,843
Taiwan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	305	1,747	3,218	7,780
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,629	199	3,270	470
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	1,332	1,258	3,853	4,218
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	104	296	718	982
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	300	471	715	616
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	84	191	327	616
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenue	$ 5	$ 229	$ 525	$ 527