Collaboration and Licensing Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands			1 Months Ended		3 Months Ended								12 Months Ended
	Oct. 15, 2020 USD ($) item	May 17, 2018 USD ($) item $ / shares shares	Oct. 31, 2020 USD ($) $ / shares shares	Apr. 30, 2013 item	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Purchase of common stock value														$ 136,498	$ 92,063
Revenue from contract with customer					$ 112,089	$ 9,266	$ 5,634	$ 8,093	$ 4,511	$ 5,785	$ 5,208	$ 4,382	$ 135,082	19,886	13,469
Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer													$ 643	140	33
Vifor Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of net profit sharing			60.00%
Number of days to terminate agreement													60 days
Vifor Agreement [Member] | License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 50,000
Percentage of premium on common stock investment	20.00%
Stock issuance price measurement period	30 days
Number of performance obligations for revenue recognized | item	1
Revenue from contract with customer													$ 111,551
VFMCRP Agreement [Member] | Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer													115
Cost of clinical compound related to R&D expense													$ 108
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable, non-creditable upfront payment		$ 50,000
Common stock, shares issued | shares		1,174,827
Purchase of common stock value		$ 20,000
Purchase common stock per share amount | $ / shares		$ 17.024
Closing prices of company common stock description		over a pre-determined average closing price of the Company’s common stock.
Premium from sale of stock		$ 5,444
Contract liabilities		$ 55,444
Number of combined performance obligations for revenue recognized | item		1
Number of performance obligations for revenue recognized | item		2
Number of days to terminate agreement													60 days
Termination notice effective period													12 months
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Third-party cost for clinical development		$ 20,000
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member] | Maximum [Member] | Regulatory and Commercial Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		470,000
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member] | Maximum [Member] | Regulatory Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		30,000
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member] | Maximum [Member] | Tiered Commercial Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		$ 440,000
Maruishi Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of performance obligations for revenue recognized | item				2
Cost of clinical compound related to R&D expense													$ 476	126	30
Maruishi Pharmaceutical Co., Ltd. [Member] | Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer													$ 528	$ 140	$ 33
Vifor International Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of performance obligations for revenue recognized | item	1
Vifor International Ltd. [Member] | Regulatory and Commercial Milestones [Member] | License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments			$ 50,000
Vifor International Ltd. [Member] | Vifor Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of net profit sharing			40.00%
Vifor International Ltd. [Member] | Vifor Agreement [Member] | License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable, non-creditable upfront payment			$ 100,000
Common stock, shares issued | shares			2,939,552
Purchase common stock per share amount | $ / shares			$ 17.0094
Premium from sale of stock			$ 11,551
Vifor International Ltd. [Member] | Maximum [Member] | Tiered Commercial Milestones [Member] | License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 240,000