ACQUISITION - Summary of Unaudited Proforma Financial Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Business Combinations [Abstract]
Net revenues	$ 82,972	$ 247,260
Net loss	$ (15,454)	$ (45,173)
Basic and diluted net loss per share (in dollars per share)	$ (0.77)	$ (2.27)
Weighted average shares outstanding used in computing basic and diluted net loss per share (in shares)	20,206	19,968