Revenue Recognition - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,569	$ 2,135
Collaborative revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,198	788
Collaborative revenue | Affiliated Entity [Member] | CSL Vifor Profit Sharing
Disaggregation of Revenue [Line Items]
Total revenue	1,198	788
Collaborative revenue | Affiliated Entity [Member] | CSL Vifor | CSL Vifor Profit Sharing
Disaggregation of Revenue [Line Items]
Total revenue	1,198	788
Commercial supply revenue
Disaggregation of Revenue [Line Items]
Total revenue		640
Commercial supply revenue | Affiliated Entity [Member] | CSL Vifor
Disaggregation of Revenue [Line Items]
Total revenue	0	640
Commercial supply revenue | Affiliated Entity [Member] | CSL Vifor | CSL Vifor Korsuva [Member]
Disaggregation of Revenue [Line Items]
Total revenue		640
Clinical compound revenue
Disaggregation of Revenue [Line Items]
Total revenue	48	84
Clinical compound revenue | Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	48	84
Other revenue (non-cash)
Disaggregation of Revenue [Line Items]
Total revenue	1,323	623
Other revenue (non-cash) | Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	950	333
Other revenue (non-cash) | Affiliated Entity [Member] | CSL Vifor Kapruvia [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 373	$ 290