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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2006
Commitments And Contingencies [Line Items] |  |  |
Restricted time deposits | $ 2,072 | $ 4,145 |
Lease obligation liability | 1,925 |  |
Research and Pre-Clinical Stage Development Programs [Member] |  |  |
Commitments And Contingencies [Line Items] |  |  |
Maximum future milestone payments | 11,000 |  |
FibroGen, Inc. [Member] |  |  |
Commitments And Contingencies [Line Items] |  |  |
Restricted time deposits |  |  | $ 7,300
Prior period reclassification adjustment | $ 2,100 |  |
Description of lessee leasing arrangements, operating leases | The agreement also included an expansion option to occupy part of an adjacent building, for which the Company gave notice to its landlord that it would not exercise this expansion option |  |
Lease incentive receivable from land lord through expansion option not used | $ 5,000 |  |
Lease obligation liability | 1,500 |  |
FibroGen, Inc. [Member] | Accrued and Other Current Liabilities [Member] |  |  |
Commitments And Contingencies [Line Items] |  |  |
Lease obligation liability | 400 |  |
FibroGen, Inc. [Member] | Long Term Portion of Lease Obligations [Member] |  |  |
Commitments And Contingencies [Line Items] |  |  |
Lease obligation liability | $ 1,100 |  |

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- Definition Commitments and contingencies. + References No definition available. + Details
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- Definition Maximum future milestone payments. + References No definition available. + Details
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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=82846649&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=84164451&loc=d3e36991-112694 + Details
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- Definition This item represents a receivable for an incentive or inducement contractually stipulated between parties to a lease whereby the lessor has committed to provide the entity (lessee) with a cash payment as inducement to enter the lease. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 25 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e40019-112707 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 25 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e40010-112707 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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