Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 30, 2022	Mar. 31, 2022	Jan. 31, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party				$ 8,003		$ 8,003
Total revenue				23,003		27,793	$ 1,935
Commercial Supply Revenue
Collaboration Arrangement [Line Items]
Total revenue						4,790
License and Milestone Fees
Collaboration Arrangement [Line Items]
Total revenue				15,000		15,000	1,192
Collaborative Revenue
Collaboration Arrangement [Line Items]
Total revenue				8,003		8,003	706
Clinical Compound Revenue
Collaboration Arrangement [Line Items]
Total revenue							37
Vifor Agreement No 2 [Member] | License and Milestone Fees
Collaboration Arrangement [Line Items]
Total revenue	$ 15,000
Vifor International Supply Agreement [Member] | Commercial Supply Revenue
Collaboration Arrangement [Line Items]
Total revenue				0
Vifor, Vifor International, Maruishi and CKDP Agreements [Member]
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party								$ 0
Other contract Assets				0		0		0
Other contract liabilities				0		0		$ 0
Maruishi Agreement [Member] | License and Milestone Fees
Collaboration Arrangement [Line Items]
Total revenue				0	$ 0	0	1,192
Maruishi Agreement [Member] | Collaborative Revenue
Collaboration Arrangement [Line Items]
Total revenue				0	0	0	706
Maruishi Agreement [Member] | Clinical Compound Revenue
Collaboration Arrangement [Line Items]
Total revenue							37
Maruishi Pharmaceutical Co., Ltd. [Member] | Clinical Compound Revenue
Collaboration Arrangement [Line Items]
Total revenue				0	$ 0	0	$ 37
Vifor [Member]
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party				8,003		8,003
Vifor [Member] | Commercial Supply Revenue
Collaboration Arrangement [Line Items]
Total revenue						4,790
Vifor [Member] | Commercial Supply Revenue With No Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Revenue			$ 2,295
Cost of goods sold			$ 0
Vifor [Member] | Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Revenue		$ 2,495
Cost of goods sold		$ 2,081
Vifor [Member] | Collaborative Revenue
Collaboration Arrangement [Line Items]
Revenue for profit-share				$ 8,003		$ 8,003