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SHAREHOLDERS' EQUITY - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Apr. 26, 2017 | Feb. 13, 2017 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
STOCK BASED COMPENSATION |  |  |  |  |  |
Stock options granted (in shares) |  |  | 3,050,000 | 375,000 | 338,000 |
Exercise price of options granted (in dollars per share) |  |  | $ 1.73 | $ 1.90 | $ 2.99 |
Exercisable period of options |  |  | 1 year 2 months 12 days |  |  |
Number of common stock reserved for issuance |  |  | 17,500,000 |  |  |
Number of shares of common stock reserved for issuance |  |  | 4,221,023 | 5,776,483 |  |
Common stock issued |  |  | 400,339,000 | 344,560,000 |  |
Maximum number of shares that may be subject to grants of options to an individual in a calendar year |  |  | 1,000,000 |  |  |
Shares |  |  |  |  |  |
Balance at the beginning of the period (in shares) |  |  | 4,243,000 | 4,906,000 | 4,720,000 |
Granted (in shares) |  |  | 3,050,000 | 375,000 | 338,000 |
Exercised (in shares) |  |  | (535,000) | (171,000) | (94,000) |
Forfeited (in shares) |  |  | (700,000) | (405,000) | (37,000) |
Expired (in shares) |  |  | (789,000) | (462,000) | (21,000) |
Balance at the end of the period (in shares) |  |  | 5,269,000 | 4,243,000 | 4,906,000 | 4,720,000
Exercisable at the end of the period (in shares) |  |  | 2,234,000 |  |  |
Weighted Average Exercise Price |  |  |  |  |  |
Balance at the beginning of the period (in dollars per share) |  |  | $ 2.33 | $ 2.45 | $ 2.41 |
Granted (in dollars per share) |  |  | 1.73 | 1.90 | 2.99 |
Exercised (in dollars per share) |  |  | $ 1.01 | $ 1.02 | $ 1.30 |
Proceeds from exercise of stock options |  |  | $ 544 | $ 192 | $ 121 |
Forfeited (in dollars per share) |  |  | $ 2.56 | $ 3.99 | $ 4.28 |
Expired (in dollars per share) |  |  | 2.90 | 2.27 | 5.00 |
Balance at the end of the period (in dollars per share) |  |  | 2.00 | $ 2.33 | $ 2.45 | $ 2.41
Exercisable (in dollars per share) |  |  | $ 2.27 |  |  |
Weighted Average Remaining Contractual Life |  |  |  |  |  |
Outstanding at the end of the period |  |  | 3 years | 2 years | 2 years 7 months 6 days | 3 years 4 months 24 days
Exercisable period of options |  |  | 1 year 2 months 12 days |  |  |
Intrinsic Value |  |  |  |  |  |
Outstanding at the beginning of the period (in dollars) |  |  | $ 1,475 | $ 2,564 | $ 4,388 |
Exercised (in dollars) |  |  | 419 | 195 | 87 |
Outstanding at the end of the period (in dollars) |  |  | 364 | $ 1,475 | $ 2,564 | $ 4,388
Exercisable at the end of the period (in dollars) |  |  | $ 364 |  |  |
Granted (in shares) |  |  | 3,050,000 | 375,000 | 338,000 |
Equity Incentive Plan |  |  |  |  |  |
STOCK BASED COMPENSATION |  |  |  |  |  |
Common stock issued |  |  | 535,000 | 171,000 |  |
Weighted Average Exercise Price |  |  |  |  |  |
Exercised (in dollars per share) |  |  | $ 1.02 | $ 1.02 |  |
Proceeds from exercise of stock options |  |  | $ 500 | $ 200 |  |
Lexam VG Gold |  |  |  |  |  |
STOCK BASED COMPENSATION |  |  |  |  |  |
Share replacement awards | $ 100 |  |  |  |  |
Ratio of Company's share for acquired company's share |  | 0.056% |  |  |  |
Certain employees and directors |  |  |  |  |  |
STOCK BASED COMPENSATION |  |  |  |  |  |
Stock options granted (in shares) |  |  | 3,100,000 | 400,000 | 300,000 |
Exercise price of options granted (in dollars per share) |  |  | $ 1.73 | $ 1.90 | $ 2.99 |
Shares |  |  |  |  |  |
Granted (in shares) |  |  | 3,100,000 | 400,000 | 300,000 |
Weighted Average Exercise Price |  |  |  |  |  |
Granted (in dollars per share) |  |  | $ 1.73 | $ 1.90 | $ 2.99 |
Intrinsic Value |  |  |  |  |  |
Granted (in shares) |  |  | 3,100,000 | 400,000 | 300,000 |
Vesting period of options |  |  | 3 years |  |  |
Exercise period of options |  |  | 5 years |  |  |

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