Segment Information - Summary of Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 2,456	$ 5,346	$ 7,106	$ 8,910	$ 8,912	$ 8,036	$ 14,469	$ 14,268	$ 23,818	$ 45,685	$ 41,513
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									5,499	19,857	14,844
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,646	5,001	2,214
Taiwan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,490	9,843	7,361
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,718	925	436
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									4,894	5,452	4,444
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									785	1,169	455
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									913	716	10,368
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									342	1,517	309
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									9	229	745
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 522	$ 976	$ 337