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STOCKHOLDERS' EQUITY - EQUITY PLANS (Details) - USD ($) | 1 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
May 31, 2023 | May 31, 2022 | May 31, 2021 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2018 | Oct. 31, 2018 | May 15, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock, shares reserved for future issuance (in shares) |  |  |  | 186,385,839 |  |  |  |  |
Shares available for grant |  |  |  | 58,750,670 | 18,370,729 |  |  |  |
Aggregate Intrinsic Value - Options Outstanding |  |  |  |  |  |  |  |  |
Closing stock price (in dollars per share) |  |  |  | $ 2.11 |  |  |  |  |
Total pretax intrinsic value of stock options exercised (in dollars) |  |  |  | $ 11,986,000 | $ 787,000 | $ 93,000 |  |  |
Cash received from exercise of stock options (in dollars) |  |  |  | $ 12,356,000 | $ 1,799,000 | $ 556,000 |  |  |
Number of Shares - Options Outstanding |  |  |  |  |  |  |  |  |
Stock options exercisable at the end of the period (in shares) |  |  |  | 39,995,642 | 36,085,389 | 30,459,136 |  |  |
Weighted Average Exercise Price Per Share - Options Outstanding |  |  |  |  |  |  |  |  |
Stock options exercisable at the end of the period (in dollars per share) |  |  |  | $ 2.16 | $ 2.17 | $ 2.35 |  |  |
2011 Plan |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period of stock options |  |  |  | 4 years |  |  |  |  |
2011 Plan | Maximum |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Expiration term of stock options from date of grant |  |  |  | 10 years |  |  |  |  |
2018 Plan |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period of stock options |  |  |  | 4 years |  |  |  |  |
Common stock, shares reserved for future issuance (in shares) |  |  |  |  |  |  |  |  | 10,000,000
Minimum percentage of ownership required for granting stock options at least 110% of fair market value of common stock |  |  |  | 10.00% |  |  |  |  |
Minimum exercise price as a percentage of fair market value for employees having more than 10 % outstanding common stock |  |  |  | 110.00% |  |  |  |  |
Maximum expiration term of stock options granted to employees having more than 10 % outstanding common stock |  |  |  | 5 years |  |  |  |  |
Common stock, increase in shares reserved for future issuance (in shares) | 43,360,000 | 11,000,000 | 12,500,000 |  |  |  |  |  |
2018 Plan | First Director Option |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period of stock options |  |  |  | 3 years |  |  |  |  |
Stock options to be granted to purchase shares upon appointment (shares) |  |  |  | 200,000 |  |  |  |  |
2018 Plan | Subsequent Director Option |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock options to be granted to purchase shares (in shares) |  |  |  | 125,000 |  |  |  |  |
2018 Plan | Maximum |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Expiration term of stock options from date of grant |  |  |  | 10 years |  |  |  |  |
2006 Directors Plan | First Director Option |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period of stock options |  |  |  | 3 years |  |  |  |  |
2006 Directors Plan | Subsequent Director Option |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period of stock options |  |  |  | 1 year |  |  |  |  |
2006 Directors Plan | Maximum |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Expiration term of stock options from date of grant |  |  |  | 10 years |  |  |  |  |
2018 Inducement Award Plan |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock, shares reserved for future issuance (in shares) |  |  |  | 32,306,638 |  |  | 3,000,000 |  |
Common stock, increase in shares reserved for future issuance (in shares) | 13,900,000 |  |  |  |  |  |  |  |
Shares available for grant |  |  |  | 11,616,841 |  |  |  |  |
Directors Market Value Stock Purchase Plan |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock, shares reserved for future issuance (in shares) |  |  |  |  |  |  |  | 1,000,000 |
Directors Market Value Stock Purchase Plan | Restricted stock awards |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares issued (in shares) |  |  |  | 36,864 | 15,962 | 20,783 |  |  |
Weighted average grant date fair value (in dollars per share) |  |  |  | $ 2.37 | $ 1.92 | $ 1.38 |  |  |
Total fair value of restricted stock that vested |  |  |  | $ 85,400 | $ 29,000 | $ 29,000 |  |  |

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