Segment, Customer and Geographic Information - Revenues Attributable to Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Products	$ 21,308	$ 23,032	$ 40,491	$ 46,189
Services	2,935	4,593	4,826	7,762
Total revenues	24,243	27,625	45,317	53,951
Cost of revenues:
Products	12,203	14,052	23,754	27,542
Services	2,803	4,224	5,275	6,890
Total cost of revenues	$ 15,006	$ 18,276	$ 29,029	$ 34,432