Segment, Customer Concentration and Geographical Information - Company Revenue in Different Geographic Locations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue from External Customer [Line Items]
Total revenues	$ 5,862	$ 7,459	$ 11,438	$ 14,673
Americas [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues	5,763	7,302	11,236	14,444
EMEA [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues	31	103	81	164
Asia Pacific [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues	$ 68	$ 54	$ 121	$ 65