Segment, Customer Concentration and Geographical Information - Company Revenue in Different Geographic Locations (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
Revenue from External Customer [Line Items]
Total revenues	$ 10,006	$ 9,586	$ 9,386	$ 10,529	$ 10,554	$ 9,448	$ 8,528	$ 8,449	$ 39,507	$ 36,979	$ 42,675
Americas [Member]
Revenue from External Customer [Line Items]
Total revenues									39,008	35,689	38,532
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenues									260	326	928
EMEA [Member]
Revenue from External Customer [Line Items]
Total revenues									$ 239	$ 964	$ 3,215