ACCOUNTING STANDARDS AND SIGNIFICANT ACCOUNTING POLICIES - Effect of Topic 606 Adoption On Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets:
Accounts receivable, net	$ 6,727	$ 4,171
Prepaid expenses		2,545
Liabilities:
Deferred revenue		3,291
Deferred revenue — related party	1,940	1,986
Deferred income tax liabilities, net	$ 1,823	4,490
Amount As reported
Assets:
Accounts receivable, net		4,137
Prepaid expenses		8,957
Liabilities:
Deferred revenue		22,011
Deferred revenue — related party		5,115
Deferred income tax liabilities, net		614
Adjustments | Topic 606
Assets:
Accounts receivable, net		34
Prepaid expenses		(6,412)
Liabilities:
Deferred revenue		(18,720)
Deferred revenue — related party		(3,129)
Deferred income tax liabilities, net		$ 3,876