ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Effect of Topic 606 on Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Deferred tax assets	$ 74,897		$ 68,394	$ 68,126
Total assets	664,359			640,423
Liabilities
Accrued expenses and other current liabilities	54,258		67,335	66,308
Total current liabilities	146,037			172,293
Total liabilities	699,659			668,474
Shareholders' Deficit
Accumulated deficit	(370,221)		(360,531)	(359,772)
Total shareholders' (deficit) equity	$ (35,300)		(28,810)	(28,051)
Before adoption of ASC 606 | ASU 2014-09
Assets
Deferred tax assets		$ 74,900		74,624
Total assets		664,362		664,086
Liabilities
Accrued expenses and other current liabilities		54,267		53,210
Total current liabilities		146,046		144,989
Total liabilities		699,668		698,611
Shareholders' Deficit
Accumulated deficit		(370,227)		(369,446)
Total shareholders' (deficit) equity		(35,306)		(34,525)
Adjustments | ASU 2014-09
Assets
Deferred tax assets		3	268	(273)
Total assets		3		(273)
Liabilities
Accrued expenses and other current liabilities		9	1,027	(1,048)
Total current liabilities		9		(1,048)
Total liabilities		9		(1,048)
Shareholders' Deficit
Accumulated deficit		(6)	$ (759)	775
Total shareholders' (deficit) equity		$ (6)		$ 775