SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Right of use lease assets, net	$ 11,924	$ 12,600	$ 0
Lease liability	12,340	$ 12,900
Transaction price allocated to unsatisfied performance obligation	6,200
Unearned revenues	2,600		$ 1,700
Revenues recognized that was included in the deferred revenue balance	$ 4,700