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Liquidity and Going Concern - Additional Information (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Liquidity [Abstract] |  |  |  |  |  |  |  |  |
Net loss | $ 1,728 | $ 1,839 | $ 1,087 | $ (526) | $ 9,147 | $ 3,150 | $ 4,654 | $ 11,771 |
Accumulated deficit | $ (429,924) |  |  |  |  |  | (429,924) |  | $ (425,270)
Net cash used in operating activities |  |  |  |  |  |  | $ (5,210) | $ (6,942) |
Substantial doubt about going concern, description |  |  |  |  |  |  | These factors raise substantial doubt about the Company’s ability to continue as a going concern |  |

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