ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Effect of Topic 606 on Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Deferred tax assets	$ 71,967	$ 68,394	$ 68,126
Total assets	675,629		640,423
Liabilities
Accrued expenses and other current liabilities	54,790	67,335	66,308
Total current liabilities	148,872		172,293
Total liabilities	701,233		668,474
Shareholders' Deficit
Accumulated deficit	(365,852)	(360,531)	(359,772)
Total shareholders' (deficit) equity	(25,604)	(28,810)	(28,051)
Before adoption of ASC 606 | ASU 2014-09
Assets
Deferred tax assets	71,991		71,718
Total assets	675,653		675,380
Liabilities
Accrued expenses and other current liabilities	54,882		53,834
Total current liabilities	148,964		147,916
Total liabilities	701,325		700,277
Shareholders' Deficit
Accumulated deficit	(365,920)		(365,145)
Total shareholders' (deficit) equity	(25,672)		(24,897)
Adjustments | ASU 2014-09
Assets
Deferred tax assets	24	268	(249)
Total assets	24		(249)
Liabilities
Accrued expenses and other current liabilities	92	1,027	(956)
Total current liabilities	92		(956)
Total liabilities	92		(956)
Shareholders' Deficit
Accumulated deficit	(68)	$ (759)	707
Total shareholders' (deficit) equity	$ (68)		$ 707