Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Collaboration Arrangement [Line Items]
Total revenue	$ 2,569	$ 2,135
Accounts receivable, net - related party	1,229		$ 407
Other receivables	1,009		4,088
Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue	1,198	788
Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue		640
Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue	48	84
Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	1,323	623
CSL Vifor, Maruishi and CKDP Agreements [Member]
Collaboration Arrangement [Line Items]
Other contract Assets	0		0
Other contract liabilities	0		0
Maruishi Agreement [Member]
Collaboration Arrangement [Line Items]
Other receivables	950		1,047
Maruishi Agreement [Member] | Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue	48	84
Maruishi Agreement [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	950	333
Affiliated Entity [Member] | CSL Vifor Profit Sharing | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue	1,198	788
Affiliated Entity [Member] | CSL Vifor Kapruvia [Member] | Other revenue (non-cash) [Member]
Collaboration Arrangement [Line Items]
Total revenue	373	290
Affiliated Entity [Member] | CSL Vifor
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	1,229		$ 407
Affiliated Entity [Member] | CSL Vifor | Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue	0	640
Affiliated Entity [Member] | CSL Vifor | Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Cost of goods sold		620
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Profit Sharing | Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue	1,198	788
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member]
Collaboration Arrangement [Line Items]
Net sales	$ 2,429	1,806
Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member] | Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue		$ 640