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Stockholders' Equity (Tables) | 6 Months Ended
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Jun. 30, 2020
Stockholders Equity Note [Abstract] |
Schedule of Common Stock Reserved for Future Issuance | The Company had reserved common stock, on an if-converted basis, for issuance as follows:
|  | June 30, |  |  | December 31, |
|  | 2020 |  |  | 2019 |
Common stock options issued and outstanding |  |  | 5,309,239 |  |  |  | 3,872,664 |
Restricted common stock units issued and outstanding |  |  | 774,991 |  |  |  | 335,799 |
Remaining shares reserved for issuance under 2004 and 2018 Equity Incentive Plan |  |  | 1,970,938 |  |  |  | 2,750,416 |
Shares reserved for issuance under 2018 Employee Stock Purchase Plan |  |  | 483,066 |  |  |  | 326,542 |
Warrants to purchase common stock |  |  | 153,070 |  |  |  | 71,813 |
Total |  |  | 8,691,304 |  |  |  | 7,357,234 |

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