Revenue Recognition - Additional Information (Detail) $ in Thousands	1 Months Ended		11 Months Ended	12 Months Ended
	Apr. 30, 2022 USD ($) item	Jan. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($) item	Dec. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($) item	Dec. 31, 2018 item
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party				$ 407	$ 2,765
Total revenue				7,137	20,968	$ 41,867
Accrued professional fees and other				1,909	3,147
Other receivables				4,088	555
Receivable for additional HCR financing earned				2,500
HCR Agreement [Member]
Collaboration Arrangement [Line Items]
Receivable for additional HCR financing earned				2,500
Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue				2,086	12,936	16,572
Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue				640	5,843	10,223
License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue					910	15,000
Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue					415	$ 72
Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue				84	165
Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue				4,327	699
Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member]
Collaboration Arrangement [Line Items]
Number of performance obligations for revenue recognized | item							2
Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member] | License and milestone fees [Member] | Regulatory Milestones [Member]
Collaboration Arrangement [Line Items]
Number Of Combined Performance Obligation At Contract Inception | item	1
CSL Vifor, Maruishi and CKDP Agreements [Member]
Collaboration Arrangement [Line Items]
Other contract Assets				$ 0	$ 0
CSL Vifor and CKDP Agreements [Member] | License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Number of performance obligations for revenue recognized | item				1	1	1
Maruishi Agreement [Member]
Collaboration Arrangement [Line Items]
Other receivables				$ 1,047	$ 415
Remaining performance obligations				0
Maruishi Agreement [Member] | Regulatory Milestones [Member]
Collaboration Arrangement [Line Items]
Total revenue					1,449
Maruishi Agreement [Member] | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue				0	539	$ 0
Maruishi Agreement [Member] | License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue				0	910	0
Maruishi Agreement [Member] | Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue				84	165	0
Maruishi Agreement [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue				2,835	415
CSL Vifor | License and milestone fees [Member] | Regulatory Milestones [Member]
Collaboration Arrangement [Line Items]
Total revenue	$ 15,000
Affiliated Entity [Member] | CSL Vifor Profit Sharing | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue				2,086	12,397	16,572
Affiliated Entity [Member] | CSL Vifor | License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue						15,000
Affiliated Entity [Member] | CSL Vifor Kapruvia [Member] | Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue					415	72
Affiliated Entity [Member] | CSL Vifor Kapruvia [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue				1,492	284
Affiliated Entity [Member] | CSL Vifor
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party				407	2,765
Affiliated Entity [Member] | CSL Vifor | Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue				640	5,843	10,223
Affiliated Entity [Member] | CSL Vifor | Commercial Supply Revenue With No Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Total revenue		$ 2,295
Cost of goods sold		$ 0
Affiliated Entity [Member] | CSL Vifor | Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Total revenue			$ 7,928	640	5,843
Cost of goods sold			$ 7,266	620	6,174
Affiliated Entity [Member] | CSL Vifor | License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue						15,000
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Profit Sharing | Collaborative revenue
Collaboration Arrangement [Line Items]
Negative profit share for the Company				1,639
Affiliated Entity [Member] | CSL Vifor | Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member] | Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue				$ 0	$ 0	$ 0