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Summary of Significant Accounting Policies - Additional Information (Detail) |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 16, 2021 USD ($) | Dec. 31, 2021 USD ($) Segment | Dec. 31, 2020 USD ($) | Apr. 01, 2020 USD ($) | Jan. 01, 2019 USD ($)
Accounting Policy [Line Items] |  |  |  |  |
Number of operating segment | Segment |  | 1 |  |  |
Currency translation adjustment |  |  |  | $ 1,300,000 |
Highly liquid investment maturity period |  | three months or less |  |  |
Restricted time deposits |  | $ 2,100,000 | $ 2,100,000 |  |
Cash and cash equivalents |  | $ 171,223,000 | 678,393,000 |  |
Short term investments maturity |  | 12 months |  |  |
Long term Investments Maturity |  | 12 months |  |  |
Impairment of long-lived assets |  | $ 0 |  |  |
Description of payment term |  | The period between the transfer of control of the promised goods and when the Company receives payment is based on 60-day payment terms. |  |  |
Description of sales return |  | Distributors can request to return product to the Company only due to quality issues or for product purchased within one year prior to the product’s expiration date. |  |  |
Accumulated deficit |  | $ (1,264,034,000) | (974,011,000) |  |
Accumulated other comprehensive loss |  | (4,163,000) | (4,499,000) |  |
ASU 2018-02 [Member] | Impact of change in accounting principle upon adoption of ASU 2018-02 [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Accumulated deficit |  |  |  |  | $ 600,000
Accumulated other comprehensive loss |  |  |  |  | (600,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | ASU 2016-02 [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Accumulated deficit |  |  |  |  | $ (8,700,000)
Astellas and AstraZeneca [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Amount constrained related to drug product shipment |  | $ 88,800,000 |  |  |
AstraZeneca Agreements [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Profit share percent |  | 50.00% |  |  |
HiFiBiO Agreement [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Initial upfront payment | $ 25,000,000.0 | $ 25,000,000.0 |  |  |
Maximum additional future option, clinical, regulatory, and commercial milestone payments | $ 1,100,000 |  |  |  |
HiFiBiO Agreement [Member] | IPR&D Asset [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Initial upfront payment |  | 60,000,000.0 |  |  |
HiFiBiO Agreement [Member] | Accrued Liabilities |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Initial upfront payment |  | $ 35,000,000.0 |  |  |
Minimum [Member] | Computer Equipment [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 3 years |  |  |
Minimum [Member] | Laboratory Equipment [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 3 years |  |  |
Minimum [Member] | Machinery [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 3 years |  |  |
Minimum [Member] | Furniture and Fixtures [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 3 years |  |  |
Maximum [Member] | Computer Equipment [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 5 years |  |  |
Maximum [Member] | Laboratory Equipment [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 5 years |  |  |
Maximum [Member] | Machinery [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 5 years |  |  |
Maximum [Member] | Furniture and Fixtures [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Property and equipment estimated useful life |  | 5 years |  |  |
Foreign subsidiaries [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Cash and cash equivalents |  | $ 91,200,000 | $ 66,000,000.0 |  |
Accounts Receivable from Distributors [Member] | Credit Concentration Risk [Member] | Roxadustat [Member] |  |  |  |  |
Accounting Policy [Line Items] |  |  |  |  |
Concentration risk, percentage |  |  | 64.00% |  |

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