STOCK-BASED COMPENSATION - General and ESPP (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit on total stock-based compensation	$ 0	$ 0
Weighted-average grant date fair value of awards granted (in dollars per share)	$ 1.11	$ 1.64
Options exercised during period (in shares)	72,750	0
Issuance of common stock upon exercise of options	$ 193,000
Proceeds from exercise of stock options	193,000	$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options	$ 4,700,000
Average vesting period for recognition of unrecognized compensation expense	1 year 11 months 1 day
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, options	$ 2,300,000
Average vesting period for recognition of unrecognized compensation expense	2 years 10 months 28 days
Issuance of common stock upon exercise of options	$ 100,000
Total fair value of options vested	$ 200,000	$ 700,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in dollars per share)		$ 1.64

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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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Number of share options (or share units) exercised during the current period.

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Value of stock issued as a result of the exercise of stock options.

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