STOCK-BASED COMPENSATION - SCHEDULE OF STOCK-BASED COMPENSATION (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation, total	$ 1,222	$ 1,557
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation, total	(67)	210
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation, total	256	336
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation, total	$ 1,033	$ 1,011