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Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Issuance costs |  |  | $ 5,587
Exercise of stock options (in shares) | 421,381 |  |
Exercise of stock options | $ 1,837 | $ 3,138 |
Common Stock |  |  |
Exercise of stock options (in shares) | 421,381 | 697,428 |
Additional Paid-in Capital |  |  |
Exercise of stock options | $ 1,837 | $ 3,138 |
At market equity offering program (2018 ATM) |  |  |
Issuance costs |  | 2,176 |
Public Stock Offering |  |  |
Issuance costs |  | $ 10,809 |
At Market Equity Offering Program (2020 ATM) |  |  |
Issuance costs | $ 988 |  |

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