Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	$ 435		$ 435		$ 2,765
Total revenue	2,556	$ 4,866	5,682	$ 17,964
Accrued professional fees and other	1,418		1,418		3,147
Other receivables	934		934		555
Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue	1,298	2,471	2,086	10,631
Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue		1,252	640	5,843
License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue		910		910
Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue		167		415
Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue		66	84	165
Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	1,258	0	2,872	0
CSL Vifor, Maruishi and CKDP Agreements [Member]
Collaboration Arrangement [Line Items]
Other contract Assets	0		0		0
Other contract liabilities	0		0		0
Maruishi Agreement [Member]
Collaboration Arrangement [Line Items]
Other receivables	835		835		415
Maruishi Agreement [Member] | Regulatory Milestones [Member]
Collaboration Arrangement [Line Items]
Total revenue		1,449		1,449
Maruishi Agreement [Member] | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue		539		539
Maruishi Agreement [Member] | License and milestone fees [Member]
Collaboration Arrangement [Line Items]
Total revenue		910		910
Maruishi Agreement [Member] | Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue	0	66	84	165
Maruishi Agreement [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	823		1,788
Affiliated Entity [Member] | CSL Vifor [Member]
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	435		435		$ 2,765
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Profit Sharing [Member] | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue	1,298	1,932	2,086	10,092
Q2 negative profit share for the Company			1,447
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Korsuva [Member]
Collaboration Arrangement [Line Items]
Net sales	3,004	4,400	2,146	21,500
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Korsuva [Member] | Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue	0	1,252	640	5,843
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Korsuva [Member] | Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Cost of goods sold		1,558	620	5,566
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Kapruvia [Member] | Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue	0	$ 167	0	$ 415
Affiliated Entity [Member] | CSL Vifor [Member] | CSL Vifor Kapruvia [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	$ 435		$ 1,084