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Commitments and Contingencies - Additional Information (Details) - USD ($) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2019 | May 31, 2018 | Apr. 30, 2018 | Dec. 31, 2020 | Dec. 31, 2019
Loss Contingencies [Line Items] |  |  |  |  |
Lessee, operating lease, description | The lease term is for 24 months, expiring in January 2022 | The lease term expires in April 2021 and the Company has an option to renew for an additional 12 months. |  |  |
Operating lease, payments |  | $ 4,000 |  | $ 17,500 |
Lessee, operating lease term of contract | 24 months | 12 months |  |  | 24 months
Operating leases, rent expense |  |  |  | $ 273,000 | $ 159,000
Teva Agreements |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Nonrefundable upfront payment |  |  | $ 6,000,000 |  |
Payment upon achievement of certain clinical and commercial milestones |  |  | 135,000,000 |  |
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 |
Teva Agreements | Research and Development Expenses |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Up-front license payment |  |  |  | $ 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 |  |
Restricted Cash And Other Assets Member |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Security deposit | $ 95,000 |  |  | $ 95,000 | $ 95,000

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- Definition A general description of the nature of the existing leasing arrangements of a lessee for all operating leases including, but not limited to: (1) rental escalation clauses; (2) renewal or purchase options; (3) guarantees or indemnities, if any, (4) restrictions imposed by lease arrangements; (5) unusual provisions or conditions; (6) contingent rentals, if any; and (7) lease expiration dates. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 1) -URI http://asc.fasb.org/extlink&oid=121580752&loc=d3e38371-112697 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121549808&loc=d3e36991-112694 + Details
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