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Collaboration and Licensing Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Oct. 15, 2020 USD ($) $ / shares shares	May 17, 2018 USD ($) item $ / shares shares	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer			$ 9,266	$ 5,785	$ 22,993	$ 15,375
Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer			9		$ 616	140
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 days to terminate agreement					60 days
Termination notice effective period					12 months
Revenue from contract with customer			$ 0
Cost of clinical compound related to R&D expense					$ 79
Vifor Fresenius Medical Care Renal Pharma Ltd. [Member] \| Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer					88
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 receivable		$ 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 receivable		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 receivable		$ 440,000
Maruishi Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cost of clinical compound related to R&D expense					476	126
Maruishi Pharmaceutical Co., Ltd. [Member] \| Clinical Compound Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from contract with customer					$ 528	$ 140
Vifor International Ltd. [Member] \| Exclusive License Agreement [Member] \| Subsequent Event [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 of common stock value	$ 50,000
Purchase common stock per share amount \| $ / shares	$ 17.0094
Potential milestone payments receivable	$ 240,000