Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	$ 359		$ 359		$ 2,765
Total revenue	991	$ 6,933	3,126	$ 13,098
Accrued professional fees and other	4,754		4,754		3,147
Other receivables	764		764		555
Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue		1,400	640	4,591
Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue		123		248
Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue		5,410	788	8,160
Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue			84	99
Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	991	0	1,614	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	645		645		415
Maruishi Agreement [Member] | Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue	0	0	84	99
Maruishi Agreement [Member] | Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	632		965
Affiliated Entity [Member] | CSL Vifor
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	359		359		$ 2,765
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Profit Sharing
Collaboration Arrangement [Line Items]
Negative profit share for the Company	1,447
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Profit Sharing | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue		5,410	788	8,160
Accrued professional fees and other	1,447		1,447
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member]
Collaboration Arrangement [Line Items]
Net sales	(2,664)	11,467	(858)	17,141
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member] | Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue	0	1,400	640	4,591
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member] | Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Cost of goods sold		1,418	620	4,008
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Kapruvia [Member] | Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue	0	$ 123	0	$ 248
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Kapruvia [Member] | Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	$ 359		$ 649