Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2022 USD ($) shares	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2022 USD ($) shares	Jun. 30, 2021 USD ($) ft²	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Nov. 30, 2020 $ / shares shares	Oct. 31, 2020 shares
Significant Accounting Policies [Line Items]
Restricted cash deposit		$ 2,070		$ 2,070		$ 2,070
Restricted cash noncurrent	$ 2,070	1,833	$ 2,070	1,833	$ 2,070	2,070	$ 327
Restricted cash current	$ 90	237	90	237	90
Right of use asset		$ 28,939		$ 28,939		$ 1,142
Common stock, shares issued | shares		112,964,698		112,964,698		110,340,281
Payment of exchange fees		$ 268	$ 102	$ 503	$ 187
Common stock shares issued warrant to purchase | shares								30,000
Common stock warrants exercise price per share | $ / shares								$ 3.29
Agreement termination period				60 days
Agreement written notice period				30 days
Ultragenyx [Member] | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member]
Significant Accounting Policies [Line Items]
Common stock, shares issued | shares									7,825,797
Office laboratory [Member] | Hood Park LLC [Member]
Significant Accounting Policies [Line Items]
Area of lease agreement | ft²	49,869		49,869		49,869
Lease description				The Company relocated its corporate headquarters to the Premises in June 2022. The initial term of the lease commenced in June 2022 when the construction of the lessor assets was substantially completed and continues for a ten-year period, unless earlier terminated. The lease provides the Company with an option to extend the lease for an additional five-year term. The Company and the Landlord were each obligated to undertake certain improvements prior to the commencement of the lease, and significant improvements were completed as of June 2022.
Operating lease, monthly payments	$ 305
Operating lease payments annual escalation percentage	3.00%
Construction allowance	$ 10,223
Letter of credit amount		1,833		$ 1,833
Right of use asset		28,939		28,939
Lease liability		$ 24,576		$ 24,576