Segment Information - Summary of Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 4,722	$ 7,086	$ 3,535	$ 4,287	$ 2,456	$ 5,346	$ 7,106	$ 8,910	$ 19,630	$ 23,818
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									8,945	3,718
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									3,364	4,894
Malaysia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									2,880
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									1,486	3,646
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									876	522
Taiwan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									847	3,490
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									509	913
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									398	785
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									222	5,499
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 103	$ 351