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Income Taxes - Additional Information (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Income Tax Disclosure [Line Items] |  |  |
Valuation allowance | $ 11,814 | $ 8,088 | $ 7,753
Change in valuation allowance |  | 3,726 | 335
Deferred income tax assets | $ 12,862 | 8,466 |
Federal credits begin to expire | 2020 |  |
Unrecognized tax benefits accounted for as a reduction in deferred tax assets | $ 5,284 |  |
Unrecognized tax benefits would affect the effective tax rate if recognized | 1,615 |  |
Unrecognized tax benefits | 6,900 | 5,957 | 1,347
Accrued interest and penalties related to unrecognized tax benefits | 229 | 58 |
Accrued liability for Interest and penalties related to unrecognized tax benefits | 356 | 126 |
Federal |  |  |
Income Tax Disclosure [Line Items] |  |  |
Research and development tax credit | 632 | 467 |
California |  |  |
Income Tax Disclosure [Line Items] |  |  |
Research and development tax credit | 117 | 91 |
Expire Beginning in 2020 |  |  |
Income Tax Disclosure [Line Items] |  |  |
Net operating loss carryovers | 24,367 |  |
Federal |  |  |
Income Tax Disclosure [Line Items] |  |  |
Net operating loss carryovers | 42,415 | 24,411 | $ 18,048
State |  |  |
Income Tax Disclosure [Line Items] |  |  |
Net operating loss carryovers | $ 11,492 | $ 9,580 |

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