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Stockholders' Equity - Additional Information (Details) - $ / shares |  | 1 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | ---
Oct. 01, 2018 | Aug. 31, 2017 | Sep. 30, 2020 | Feb. 28, 2020 | Dec. 31, 2019
Stockholders Equity [Line Items] |  |  |  |  |
Voting rights per share |  |  | one vote per share |  |
Preferred stock shares authorized |  |  | 10,000,000 |  | 10,000,000
Preferred stock, par value |  |  | $ 0.001 |  | $ 0.001
Preferred stock, outstanding |  |  | 0 |  | 0
Loan and Security Agreement | Oxford Finance LLC |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares |  |  |  | 54,171 |
Loan and Security Agreement | Silicon Valley Bank |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares |  |  |  | 27,086 |
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares |  |  |  | 81,257 |
Exercise price per share |  |  |  | $ 9.23 |
Series E Redeemable Convertible Preferred Stock |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares | 46,359 |  |  |  |
Preferred stock, conversion basis | 1-for-0.0275 |  |  |  |
Series C Redeemable Convertible Preferred Stock |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares | 25,454 |  |  |  |
Preferred stock, conversion basis | 1-for-0.0370 |  |  |  |
Cancellation of redeemable convertible preferred warrants | 1,232,220 |  |  |  |
Conversion of warrants to purchase of shares of common stock | 687,928 |  |  |  |
Oxford Finance LLC and Silicon Valley Bank | Series D Two Redeemable Convertible Preferred Stock | Loan and Security Agreement |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares |  | 682,230 |  |  |
Exercise price per share |  | $ 0.6596 |  |  |
Oxford Finance LLC and Silicon Valley Bank | Series E Redeemable Convertible Preferred Stock | Loan and Security Agreement |  |  |  |  |
Stockholders Equity [Line Items] |  |  |  |  |
Issuance of warrants to purchase shares |  | 1,682,871 |  |  |
Exercise price per share |  | $ 0.2674 |  |  |
Term of warrant exercisable |  | 10 years |  |  |

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