Segment Information - Summary of Revenue by Geographic Region (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 8,036	$ 11,115	$ 36,773	$ 29,977
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,851	3,775	16,721	9,569
Taiwan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,747	3,347	7,780	4,541
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,258	1,628	4,218	3,379
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	794		4,843	579
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	471	1,840	616	10,368
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	296	85	982	339
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	199	183	470	198
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	191	72	616	222
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 229	$ 185	$ 527	$ 782