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STOCK-BASED COMPENSATION - Additional Information (Details) |  |  |  |  |  |  |  | 12 Months Ended |  |
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Jun. 24, 2020 shares | Jun. 13, 2019 shares | Jan. 17, 2019 $ / shares shares | Oct. 12, 2018 $ / shares shares | May 31, 2018 shares | May 31, 2017 shares | Jun. 09, 2015 shares | Dec. 31, 2020 USD ($) $ / shares shares | Dec. 31, 2019 USD ($) $ / shares shares | Dec. 31, 2017 $ / shares shares | Jan. 01, 2020 $ / shares shares | Jan. 01, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Capital Shares Reserved for Future Issuance |  | 1,682,000 |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant |  |  |  |  |  |  |  | 675,685 |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross |  |  | 118,750 | 167,430 |  |  |  | 653,750 | 411,930 |  |  |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | $ / shares |  |  | $ 1.99 | $ 2.61 |  |  |  | $ 1.84 | $ 2.33 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares |  |  |  |  |  |  |  | $ 1.42 | $ 1.76 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $ |  |  |  |  |  |  |  | $ 389,398 | $ 715,587 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value | $ / shares |  |  |  |  |  |  |  | $ 6.62 | $ 10.62 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Option, Nonvested, Weighted Average Exercise Price | $ / shares |  |  |  |  |  |  |  | 1.44 | 1.82 |  | $ 1.82 | $ 4.14
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value | $ / shares |  |  |  |  |  |  |  | $ 1.90 | $ 3.80 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares |  |  |  |  |  |  |  | 209,354 | 203,523 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares |  |  |  |  |  |  |  |  |  |  | 361,743 | 186,895
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ |  |  |  |  |  |  |  | $ 790,035 |  |  |  |
Employee Service Share Based Compensation Nonvested Total Compensation In Current Year | $ |  |  |  |  |  |  |  | 424,673 |  |  |  |
Employee Service Share Based Compensation Nonvested Total Compensation In Year Two | $ |  |  |  |  |  |  |  | 292,129 |  |  |  |
Employee Service Share Based Compensation Nonvested Total Compensation In Year Three | $ |  |  |  |  |  |  |  | $ 73,233 |  |  |  |
Stock Option Activity [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross |  |  |  |  |  |  |  | 653,750 |  |  |  |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | $ / shares |  |  |  |  |  |  |  | $ 1.84 | $ 2.33 |  |  |
Non-vested restricted stock [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares |  |  |  |  |  |  |  | $ 0.00 | $ 0.00 |  |  |
Employee [Member] | Non-vested restricted stock [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Annual Forfeiture Rate Percentage |  |  |  |  |  |  |  | 2.00% | 2.00% |  |  |
Stock Incentive Plan 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized | 700,000 | 700,000 |  |  | 120,000 | 120,000 |  |  |  |  |  |
Common Stock, Capital Shares Reserved for Future Issuance |  |  |  |  |  |  | 42,000 |  |  |  |  |
Stockholders' Equity Note, Stock Split, Conversion Ratio |  |  |  |  |  |  | 10 |  |  |  |  |
Stock Incentive Plan 2015 [Member] | Non-vested restricted stock [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  |  |  | 3 years |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares |  |  |  |  |  |  |  |  |  | $ 20.96 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease) |  |  |  |  |  |  |  |  |  | 8,000 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  |  | 46,000 |  |
Stock Incentive Plan 2015 [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  | 1 year |  |  |  |
Stock Incentive Plan 2015 [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  | 4 years |  |  |  |
Stock Option Plan 2006 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Capital Shares Reserved for Future Issuance |  |  |  |  |  |  |  | 7,000 |  |  |  |
Stock Option Plan 2006 [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  | 1 year |  |  |  |
Stock Option Plan 2006 [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  | 4 years |  |  |  |

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