INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Enacted Corporate Tax									35.00%
New Enacted Corporate Tax Rate									21.00%
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Unrecognized tax benefits including the impact of penalties and interest	$ 1,800				$ 1,800				$ 1,800	$ 1,800	$ 1,000
Unrecognized tax benefits that would impact effective tax rate	1,800				1,800				1,800	1,800	1,000
Reconciliation of Income Tax Provision to Statutory Tax Rate [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount									(1,975)	(4,698)	15,870
Effective Income Tax Rate Reconciliation, Tax Credit, Amount									1,277	1,646	2,468
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount									1,854	(3,113)	12,662
Effective Income Tax Rate Reconciliation, Tax Contingency, Uncertain Tax Positions									58	800	(6,710)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount									301	1,109	670
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount									0	0	2,509
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									(244)	1,455	(84)
Total (benefit from) provision for income taxes	447	$ 425	$ 144	$ 255	459	$ (1,065)	$ 587	$ 152	1,271	133	(2,875)
Income (loss) from operations before income taxes:
United States									(1,940)	(4,811)	12,402
Foreign									(7,463)	(8,611)	32,942
Total income from operations before income taxes	6,350	1,303	(8,362)	(8,694)	(422)	(993)	(10,244)	(1,763)	(9,403)	(13,422)	45,344
Current tax expense (benefit):
Net cash payments for income taxes									(2,791)	(100)	1,587
Federal									(1)	(4)	102
State									59	59	32
Foreign benefit of net operating losses									(206)	(66)	(1,247)
Other foreign									1,372	1,774	(48)
Total current tax expense (benefit)									1,224	1,763	(1,161)
Deferred tax (benefit) expense:
Federal									0	(821)	96
Other foreign									47	(809)	(1,810)
Total deferred tax (benefit) expense									47	(1,630)	(1,714)
Total (benefit from) provision for income taxes	447	$ 425	$ 144	255	459	$ (1,065)	$ 587	152	1,271	133	(2,875)
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits at beginning of period				$ 1,841				$ 1,041	1,841	1,041	25,995
Increases for tax positions taken during a prior period										800	1,041
Decreases for tax positions taken during a prior period									(78)		(25,995)
Unrecognized tax benefits at end of period	1,763				$ 1,841				1,763	$ 1,841	$ 1,041
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations									129,400
Deferred Tax Assets, Tax Credit Carryforwards	$ 800								$ 800