STOCK-BASED COMPENSATION - Restricted Stock Units Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019
Performance-based Restricted Stock Units
Number of Shares
Granted (in shares)	643,266
Weighted Average Grant Date Fair Value Per Share
Granted (in dollars per share)	$ 6.87
The 2014 Plan \| Restricted stock units
Number of Shares
Non-vested restricted stock units at the beginning of the period (in shares)	1,938,788
Granted (in shares)	2,750,408
Vested (in shares)	(873,784)
Forfeited (in shares)	(878,697)
Non-vested restricted stock units at the end of the period (in shares)	2,936,715
Weighted Average Grant Date Fair Value Per Share
Non-vested restricted stock units at the beginning of the period (in dollars per share)	$ 6.94
Granted (in dollars per share)	3.84
Vested (in dollars per share)	8.08
Forfeited (in dollars per share)	5.40
Non-vested restricted stock units at the end of the period (in dollars per share)	$ 4.64
Weighted Average Remaining Contractual Term (in years)
Non-vested restricted stock units at the end of the period	1 year 18 days
The 2014 Plan \| Performance-based Restricted Stock Units
Number of Shares
Non-vested restricted stock units at the beginning of the period (in shares)	374,824
Granted (in shares)	643,266
Vested (in shares)	0
Forfeited (in shares)	(34,247)
Non-vested restricted stock units at the end of the period (in shares)	983,843
Weighted Average Grant Date Fair Value Per Share
Non-vested restricted stock units at the beginning of the period (in dollars per share)	$ 10.14
Granted (in dollars per share)	6.87
Vested (in dollars per share)	0.00
Forfeited (in dollars per share)	6.87
Non-vested restricted stock units at the end of the period (in dollars per share)	$ 8.11
Weighted Average Remaining Contractual Term (in years)
Non-vested restricted stock units at the end of the period	1 year 8 months 16 days
Aggregate Intrinsic Value	$ 1,230

No definition available.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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