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Income Taxes - Additional Information (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Income Taxes [Line Items] |  |
Provision or benefit for income taxes | $ 0 | $ 0
Income Tax Contingency [Abstract] |  |
Valuation allowance | 102,822,000 | 101,091,000
Increase (decrease) in valuation allowance | $ 1,700,000 |
Net operating loss carryforwards, Expire date | begin to expire in 2020 and 2028 |
State tax credit carryforwards | $ 5,500,000 |
Cumulative change in ownership | 50.00% |
Period of net operating loss and R&D tax credit carry forwards to offset future taxable income | 3 years |
Liability for uncertain tax positions | $ 0 | $ 0
Period for material changes of liability for uncertain tax benefits | 12 months |
Interest related to unrecognized tax benefits in interest expense and penalties | $ 0 |
Federal [Member] |  |
Income Tax Contingency [Abstract] |  |
Tax loss carryforwards | 386,800,000 |
Federal tax carry forward | $ 6,400,000 |
Federal tax credit carryforward, Expiration date | begin to expire in 2020 |
Net operating losses | $ 21,900,000 |
Federal [Member] | Maximum [Member] |  |
Income Tax Contingency [Abstract] |  |
Percentage of federal net operating losses used to offset of future taxable income | 80.00% |
State [Member] |  |
Income Tax Contingency [Abstract] |  |
Tax loss carryforwards | $ 161,900,000 |

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