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Commitments and Contingencies - Additional Information (Details) - USD ($) |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Aug. 31, 2022 | Jan. 01, 2022 | Apr. 30, 2018 | Dec. 31, 2022 | Dec. 31, 2021
Loss Contingencies [Line Items] |  |  |  |  |
Operating lease right-of-use asset | $ 300,000 |  |  | $ 363,000 |
Operating lease liability, current | $ 300,000 |  |  | 168,000 |
Operating leases, rent expense |  |  |  | 200,000 | $ 300,000
Variable lease payments |  |  |  | 0 |
Short-term lease costs |  |  |  | $ 0 |
Remaining lease term |  |  |  | 2 years |
Incremental borrowing rate used to determine operating lease liability |  |  |  | 6.50% |
Teva Agreements |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Nonrefundable upfront payment |  |  | $ 6,000,000.0 |  |
Payment upon achievement of certain clinical and commercial milestones |  |  | 135,000,000.0 |  |
Asset transfer and license agreement, termination period after written notice |  |  |  | 120 days |
Asset transfer and license agreement, termination period notice of breach |  |  |  | 60 days |
Asset transfer and license agreement termination notice period if bankruptcy petition filed |  |  |  | 60 days |
Milestone payments |  |  |  | $ 0 | 0
Teva Agreements | Research and Development Expenses |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Milestone payments |  |  |  | $ 0 | $ 0
Teva Agreements | Teva's GlycoPEGylated FGF21 Program |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Payment upon achievement of certain clinical and commercial milestones |  |  | 67,500,000 |  |
Teva Agreements | Teva's Development Program |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Payment upon achievement of certain clinical and commercial milestones |  |  | $ 67,500,000 |  |
San Francisco Office |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Operating lease expiration month and year | 2025-01 | 2023-01 |  |  |

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