Information Regarding Net Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenue	$ 60,219	$ 56,168
Percentage of net revenue	100.00%	100.00%
Americas
Segment Reporting Information [Line Items]
Net revenue	$ 40,018	$ 38,135
Percentage of net revenue	67.00%	68.00%
Europe And Middle East
Segment Reporting Information [Line Items]
Net revenue	$ 7,887	$ 8,589
Percentage of net revenue	13.00%	15.00%
Asia-Pacific
Segment Reporting Information [Line Items]
Net revenue	$ 12,314	$ 9,444
Percentage of net revenue	20.00%	17.00%