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Summary of Significant Accounting Policies - Financial Instruments (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Nov. 25, 2019 | Jan. 31, 2020 | Dec. 31, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Class of Stock [Line Items] |  |  |  |  |
Number of warrants issued (in shares) |  |  | 467,306 | 467,306 |
Exercise price of warrants (in dollars per share) |  |  | $ 3.51 | $ 3.51 |
Amount paid for clearing fees |  | $ 231 |  |  |
Offering costs paid on the issuance of common stock and warrants |  |  |  | $ (510) | $ 0
Net proceeds from sale of common stock |  | $ 2,300 |  |  |
Percent proceeds to be paid to Lender |  | 10.00% |  |  |
Gross proceeds from equity issuance |  | $ 275 |  |  |
Payments on the Iliad Note |  |  |  | 1,306 | 0
Warrants exercised (in shares) |  | (269,240) |  |  |
Proceeds from the exercise of warrants |  |  |  | 918 | $ 0
Proceeds from warrants |  |  |  | 1,600 |
Warrant liability reclassified into equity |  |  |  | 1,405 |
Note Purchase Agreement |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Percent proceeds to be paid to Lender | 10.00% |  |  |  |
Payments on the Iliad Note |  |  |  | $ 226 |
Institutional Investor |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Number of warrants issued (in shares) |  | 688,360 |  | 425,626 |
Exercise price of warrants (in dollars per share) |  | $ 3.3700 |  |  |
Purchase price (in dollars per share) |  | $ 0.6250 |  |  |
Private Placement |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Number of warrants issued (in shares) |  | 48,185 |  | 41,680 |
Exercise price of warrants (in dollars per share) |  | $ 4.9940 |  |  |
Amount paid for placement agent commissions |  | $ 193 |  |  |
Amount paid related to expenses for registered direct offering and concurrent private placement |  | $ 50 |  |  |

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