FAIR VALUE MEASUREMENTS - Summary of changes in Level 3 instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
FAIR VALUE MEASUREMENTS
Balance at beginning of period	$ 938	$ 190
Interest accrued on face value of 5% Notes	1,023	976
Change in fair value of Level 3 liabilities	(1,601)	(228)
Balance at end of period	$ 360	$ 938

Amount of interest recognized during the period, arising from liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

No definition available.

+ Details

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- References

No definition available.

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- Definition

Amount of increase (decrease) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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