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BORROWINGS - Narrative (Details) | 1 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jul. 31, 2021 USD ($) | Mar. 31, 2020 USD ($) $ / shares shares | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Oct. 08, 2021 USD ($) | Apr. 30, 2020 USD ($) | Apr. 19, 2020 USD ($) | Dec. 31, 2018 USD ($) | Jul. 31, 2018 USD ($) $ / shares shares
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Gain (loss) on extinguishment of debt |  |  | $ 0 | $ (62,000) |  |  |  |  |
Fair value of warrants |  |  | 0 | 26,240,000 |  |  |  |  |
Interest expense |  |  | 1,886,000 | 132,000 |  |  |  |  |
Acceleration of existing indebtedness payable |  |  |  | 4,583,000 |  |  |  |  |
Series B Preferred Warrants |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Warrants issued (in shares) | shares |  |  |  |  |  |  |  |  | 100,161
Warrant exercise price (in USD per share) | $ / shares |  |  |  |  |  |  |  |  | $ 0.96
Warrants term |  |  |  |  |  |  |  |  | 10 years
Series B Preferred Warrants | Common Stock Warrants |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Fair value of warrants |  |  |  |  |  |  |  |  | $ 55,000
Preferred C warrants |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Warrants issued (in shares) | shares |  | 103,107 |  |  |  |  |  |  |
Warrant exercise price (in USD per share) | $ / shares |  | $ 1.25 |  |  |  |  |  |  |
Warrants term |  | 10 years |  |  |  |  |  |  |
Interest expense |  |  | 0 | 4,000 |  |  |  |  |
Preferred C warrants | Common Stock Warrants |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Fair value of warrants |  | $ 44,000 |  |  |  |  |  |  |
PPP loan |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt amount |  |  |  |  |  |  | $ 936,000 |  |
Interest rate |  |  |  |  |  |  | 1.00% |  |
Debt forgiveness | $ 936,000 |  |  |  |  |  |  |  |
Accrued interest | 12,000 |  |  |  |  |  |  |  |
Gain (loss) on extinguishment of debt |  |  | 948,000 |  |  |  |  |  |
Acceleration of existing indebtedness payable |  |  |  | 943,000 |  |  |  |  |
Bridge loan: |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt amount | $ 20,000,000 |  |  |  |  |  |  |  |
Interest rate | 9.00% |  |  |  |  |  |  |  |
Monthly interest rate | 0.0225 |  |  |  |  |  |  |  |
PIK interest rate | 0.0675 |  |  |  |  |  |  |  |
Final payment |  |  |  |  | $ 1,250,000 |  |  |  |
Fair value of loan at issuance |  |  | 20,000,000 |  |  |  |  |  |
Interest expense on loan |  |  | $ 1,578,000 |  |  |  |  |  |
Notes payable |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt amount |  | $ 4,000,000 |  |  |  | $ 4,000,000 |  | $ 1,000,000 |
Gain (loss) on extinguishment of debt |  |  |  | $ (62,000) |  |  |  |  |
Percent change in present value of cash flows |  | 0.10 |  |  |  |  |  |  |
Effective interest rate |  |  | 2.75% |  |  |  |  |  |
Notes payable | Prime |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Spread on interest rate |  | 0.50% |  |  |  |  |  |  |

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