Agreement termination notice period.

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Issuance of common stock to related party in connection with stock purchase agreement.

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Milestone payments upon achievement of development milestone.

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Milestone payments upon achievement of net sales milestones.

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Milestone payments upon achievement of regulatory milestone.

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Percentage of net income and net losses on net sales.

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Percentage of option to fund of development cost.

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Percentage of outstanding common stock.

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Transaction price.

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Transaction price determined under ASC 606.

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Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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The cash inflow from the additional capital contribution to the entity.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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Per share or per unit amount of equity securities issued.

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Collaborations - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended
	Oct. 22, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from issuance of common stock, net of issuance costs					$ 134,878,000
Related party revenue recognized		$ 6,169,000	$ 3,594,000	$ 8,094,000	6,929,000
Related party collaboration receivables							$ 110,000
Ultragenyx [Member] \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments upon achievement of regulatory milestone				$ 65,000,000
Percentage of option to fund of development cost				30.00%
Percentage of net income and net losses on net sales				30.00%
Agreement termination notice period				90 days
Issued and sold shares of common stock	7,825,797
Common stock issued price per share	$ 5.1113
Proceeds from issuance of common stock, net of issuance costs	$ 40,000,000
Percentage of outstanding common stock	14.45%
Transaction price determined under ASC 606				$ 22,513,000
Transaction price				0
Related party revenue recognized		6,169,000	$ 3,594,000	8,094,000	$ 6,929,000
Deferred revenue - related party		0		0		$ 6,170,000	8,080,000
Related party collaboration receivables		$ 0		0		$ 14,000	$ 110,000
Maximum [Member] \| Ultragenyx [Member] \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments upon achievement of development milestone				25,000,000
Milestone Payments upon achievement of net sales milestones				$ 165,000,000
Percentage of outstanding common stock				10.00%
Minimum [Member] \| Ultragenyx [Member] \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of outstanding common stock				10.00%