Revenue Recognition - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 41,867	$ 23,028	$ 135,082
License and Milestone Fees
Disaggregation of Revenue [Line Items]
Total revenue	15,000	21,223	134,439
License and Milestone Fees | Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	1,192	0
License and Milestone Fees | CKDP Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	0	626
License and Milestone Fees | CSL Vifor [Member]
Disaggregation of Revenue [Line Items]
Total revenue	15,000	20,031	133,813
License and Milestone Fees | Maruishi Pharmaceutical Co., Ltd. [Member]
Disaggregation of Revenue [Line Items]
Total revenue		1,192
License and Milestone Fees | Chong Kun Dang Pharmaceutical Corp. [Member]
Disaggregation of Revenue [Line Items]
Total revenue			626
Collaborative Revenue
Disaggregation of Revenue [Line Items]
Total revenue	16,572	706
Collaborative Revenue | CSL Vifor Profit Sharing [Member]
Disaggregation of Revenue [Line Items]
Total revenue	16,572
Collaborative Revenue | Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	706	0
Collaborative Revenue | CSL Vifor [Member]
Disaggregation of Revenue [Line Items]
Total revenue	16,572	0	0
Commercial Supply Revenue
Disaggregation of Revenue [Line Items]
Total revenue	10,223	701
Commercial Supply Revenue | CSL Vifor [Member]
Disaggregation of Revenue [Line Items]
Total revenue	10,223	701
Clinical Compound Revenue
Disaggregation of Revenue [Line Items]
Total revenue		398	643
Clinical Compound Revenue | CSL Vifor [Member]
Disaggregation of Revenue [Line Items]
Total revenue		361	115
Clinical Compound Revenue | Maruishi Pharmaceutical Co., Ltd. [Member]
Disaggregation of Revenue [Line Items]
Total revenue		$ 37	$ 528
Royalty Revenue
Disaggregation of Revenue [Line Items]
Total revenue	72
Royalty Revenue | CSL Vifor [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 72