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Convertible Notes - Additional Information (Details) - USD ($) |  | 1 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Nov. 30, 2019 | Apr. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019 | Dec. 31, 2018
Debt Instrument [Line Items] |  |  |  |  |  |
Proceeds from issuance of convertible notes |  |  | $ 0 | $ 19,458,000 |  |
Convertible Notes | Series C Convertible Preferred Stock |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Conversion of convertible notes payable to preferred stock | 6,893,036 |  |  |  |  |
2018 Notes |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Face amount of loans |  |  |  |  |  | $ 3,000,000
Convertible promissory notes accrued interest rate |  |  |  |  |  | 8.00%
Convertible promissory notes conversion percentage on per share price paid by investors |  |  |  |  |  | 85.00%
Qualified financing of convertible promissory notes converted into preferred equity |  |  |  |  |  | $ 10,000,000
2019 Notes |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Face amount of loans |  |  |  |  | $ 4,500,000 |
Convertible promissory notes accrued interest rate |  |  |  |  | 10.00% |
Convertible promissory notes conversion percentage on per share price paid by investors |  |  |  |  | 80.00% |
Qualified financing of convertible promissory notes converted into preferred equity |  |  |  |  | $ 10,000,000 |
Lilly Note |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Convertible promissory notes accrued interest rate |  | 8.00% |  |  |  |
Proceeds from issuance of convertible notes |  | $ 15,000,000 |  |  |  |
Maturity date |  | 2020-10 |  |  |  |
Lilly Note | Series C Convertible Preferred Stock |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Conversion of convertible notes payable to preferred stock | 4,576,342 |  |  |  |  |

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