INCOME TAXES - Reconciliation of the U.S. statutory federal income tax rate to the Company’s effective tax rate (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal tax at statutory rates	34.00%	34.00%	34.00%
State taxes, net of federal benefit	3.90%	2.10%	1.90%
Tax credits	1.60%	1.40%	1.20%
Permanent difference	2.30%	(0.60%)	(0.90%)
Foreign income taxes	0.20%	(2.90%)	(2.20%)
Change in valuation allowance	(59.70%)	(30.70%)	(29.90%)
Effect of statutory tax rate change	4.30%	(1.40%)	(1.20%)
Adjustment to net operating loss deferred tax asset	13.00%	0.00%	0.00%
Other adjustments	4.20%	(2.10%)	(3.40%)
Income tax benefit (expense)	3.80%	(0.20%)	(0.50%)

Effective Income Tax Rate Reconciliation, Change In Net Operating Loss Deferred Tax Asset, Percent

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Effective Income Tax Rate Reconciliation, Permanent Differences, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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-Publisher FASB
-Name Accounting Standards Codification
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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