v3.19.3.a.u2

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2017
At-the-Market Offerings |  |
Issuance of common stock, issuance cost | $ 6.4 |
Initial Public Offering |  |
Issuance of common stock, issuance cost |  | $ 3.1

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