License Revenue - Related Party - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Sep. 30, 2021
Related Party Transaction [Line Items]
License revenue - related party	$ 924	$ 1,173		$ 2,369	$ 5,242
Unbilled receivable from related party	519			519		$ 938
Deferred revenue current	100			100		100
Deferred revenue noncurrent	745			745		791
Zenas BioPharma Limited [Member]
Related Party Transaction [Line Items]
Reimbursement of development costs			$ 1,100
License revenue - related party	900	$ 1,200		2,400	$ 5,200
Related party receivable	200			200		4,700
Unbilled receivable from related party	500			500		900
Deferred revenue current	100			100		100
Deferred revenue noncurrent	$ 700			700		$ 800
Zenas BioPharma Limited [Member] | Milestone [Member]
Related Party Transaction [Line Items]
Development milestones			11,000
Zenas BioPharma Limited [Member] | Royalty [Member]
Related Party Transaction [Line Items]
License revenue - related party				$ 0
Zenas BioPharma Limited [Member] | Upfront Payment [Member]
Related Party Transaction [Line Items]
Upfront payments			$ 1,000				$ 1,000