Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 19, 2018
Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 3.5
Unrecognized compensation expense, recognized period	8 months 4 days
Fair value of vested awards	$ 6.6	$ 3.5	$ 2.0
Restricted Common Stock \| Employees And Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted Common Stock \| Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Performance Award I
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental compensation expense	$ 2.0
Weighted average grant date fair value (in dollars per share)	$ 1.88
Performance Award II
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental compensation expense	$ 1.1	$ 1.8
Weighted average grant date fair value (in dollars per share)	$ 1.04
Service, Performance, and Market-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	0.98	$ 0
Shares Granted (in dollars per share)	$ 0.98
Shares Granted (in shares)	1,068,000
Service and Market-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 1.80	1.67
Shares Granted (in dollars per share)	$ 1.82
Shares Granted (in shares)	1,254,000
Service-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 2.41	2.72
Shares Granted (in dollars per share)	$ 2.14	$ 2.67	$ 2.10
Shares Granted (in shares)	1,747,200	1,050,355	911,335
Service and Performance-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 2.70	$ 2.70
Shares Granted (in dollars per share)	$ 0
Shares Granted (in shares)	0
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)				15,000,000
Shares available for future awards (in shares)	12,600,000
2018 Equity Incentive Plan \| Service, Performance, and Market-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 0.98
2018 Equity Incentive Plan \| Service and Market-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 1.82
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future awards (in shares)				769,775
2013 Equity Incentive Plan \| Service and Market-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)		1.67
2013 Equity Incentive Plan \| Service and Performance-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)		$ 2.70