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STOCKHOLDERS' EQUITY DEFICIT - Equity Financing (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 1 Months Ended | 2 Months Ended | 12 Months Ended
--- | --- | --- | ---
Feb. 28, 2021 | Oct. 31, 2020 | Nov. 30, 2019 | Jun. 30, 2019 | Jul. 31, 2021 | Dec. 31, 2021 | Dec. 31, 2020
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, par value (in dollars per share) |  |  |  |  |  | $ 0.001 | $ 0.001
Aggregate sales price |  |  |  |  | $ 200.0 |  |
Proceeds from sale of stock |  |  |  | $ 27.8 |  |  |
Sale of stock, number of units issued (in shares) |  |  |  | 20.4 |  |  |
Number of warrants (in shares) |  |  |  | 20.4 |  |  |
Stock and warrants price per share (in dollars per share) |  |  |  | $ 1.47 |  |  |
Exercise price per warrant (in dollars per share) |  |  |  | $ 1.47 |  |  |
Expected term |  |  |  | 1 year |  |  |
ATM Facility |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, par value (in dollars per share) |  |  | $ 0.001 |  |  |  |
Aggregate sales price |  |  | $ 35.0 |  |  |  |
Additional shares to be issued | $ 34.5 | $ 50.0 |  |  |  |  |
Commission fixed rate |  |  | 3.00% |  |  |  |
Proceeds from sale of stock |  |  |  |  |  | $ 175.0 | $ 38.0
Sale of stock, number of units issued (in shares) |  |  |  |  |  | 56.9 | 33.4
Weighted-average stock price per share (in dollars per share) |  |  |  |  |  | $ 3.17 | $ 1.17
Issuance of common stock, issuance cost |  |  |  |  |  | $ 5.4 | $ 1.2

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