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STOCKHOLDERS' EQUITY - PUBLIC OFFERING (Details) - USD ($) |  | 12 Months Ended
--- | --- | ---
May 27, 2020 | Dec. 31, 2021 | Dec. 31, 2020
Public Offering [Line Items] |  |  |
Proceeds from exercise of warrants |  | $ 2,479,000 | $ 16,000
Underwritten Public Offering |  |  |
Public Offering [Line Items] |  |  |
Issuance of common stock in connection with public offering | 107,049,375 |  |
Net proceeds from public offering after deducting underwriting discount and other offering expenses | $ 140,184,000 |  |
Combined public offering price per share of common stock and accompanying stock purchase warrants | $ 1.30 |  |
Proceeds from exercise of warrants |  | $ 2,479,000 | $ 16,000
Underwritten Public Offering | Stock Purchase Warrants |  |  |
Public Offering [Line Items] |  |  |
Warrants to purchase common stock, exercise price | $ 1.30 |  |
Warrants to purchase common stock, shares | 57,692,307 | 55,773,466 |
Warrants to purchase common stock exercised, shares |  | 1,906,341 | 12,500
Underwritten Public Offering | Pre-Funded Warrants |  |  |
Public Offering [Line Items] |  |  |
Warrants to purchase common stock, exercise price | $ 0.001 |  |
Warrants to purchase common stock, shares | 8,335,239 | 8,335,239 |
Combined public offering price per share of pre-funded warrants and accompanying stock purchase warrants | $ 1.299 |  |

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