Collaboration and License Agreements - Glaxosmithkline Intellectual Property (No. 3) Limited - Additional Information (Detail)			3 Months Ended
	Nov. 22, 2021 USD ($) Obligation Bundle	Oct. 03, 2018 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jan. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues			$ 27,439,000	$ 21,303,000
Contract liabilities			$ 108,652,000			$ 111,055,000
Collaboration and License agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Initial transaction price		$ 252,700,000
Collaboration and License agreements | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment	$ 120,000
Milestone payment receivable at start of phase two	30,000
Milestone payment receivable upon achievement of phase two and first patient dosed in phase three	$ 100,000
Tiered royalties on net product sales receive description	The Company is further eligible to receive tiered royalties on net product sales in a range of mid-teens to twenty percent.
Collaboration and License agreements | Maximum | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Commercial milestone payments at first commercial sale	$ 190,000
Sales-related milestone payments	$ 590,000
ARO-HSD Agreement | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of distinct bundle | Bundle	1
Number of distinct performance obligations | Obligation	1
Initial transaction price	$ 120,000,000.0
Revenues	0
Contract assets	0
Contract liabilities	$ 0
ARO-HSD Agreement | GSK | Subsequent Event
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash received as due under collaboration agreement					$ 120,000,000.0