STOCKHOLDERS' EQUITY - Restricted Stock (Details) - 2020 Incentive Plan - RSU - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Stock-based compensation
Vesting period	4 years
Percentage of awards other than options vesting on the annual anniversary date of the grant	25.00%	25.00%
Number of shares granted	0.1
Fair value of grant (in dollars per share)	$ 8.00
Tranche One
Stock-based compensation
Fair value of grant (in dollars per share)		$ 11.80
Minimum \| Tranche One
Stock-based compensation
Fair value of grant (in dollars per share)		$ 4.36
Employee
Stock-based compensation
Number of shares granted		0.9
Unrecognized compensation expense other than options	$ 3,100	$ 5,600
Weighted average remaining vesting period	2 years 3 months 18 days
Employee \| Tranche One
Stock-based compensation
Vesting period		4 years
Number of shares granted		0.4
Employee \| Tranche Two
Stock-based compensation
Number of shares granted		0.2
Compensation expense recorded	$ 0
Fair value of grant (in dollars per share)		$ 11.89
Employee \| Tranche Three
Stock-based compensation
Number of shares granted		0.3
Fair value of grant (in dollars per share)		$ 6.48
Employee \| Maximum \| Tranche One
Stock-based compensation
Fair value of grant (in dollars per share)		$ 11.89
Non-employee director
Stock-based compensation
Weighted average remaining vesting period		3 years

Represents the percentage of awards other than options which vest annually on the anniversary date of the award.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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