License, Collaboration and Other Significant Agreements - Mitsubishi Tanabe Pharma Corporation Collaboration Agreement Narrative (Details)		3 Months Ended			12 Months Ended			24 Months Ended
	Dec. 11, 2015 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2021 USD ($) performance_obligation	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue under agreement					$ 213,578,000	$ 295,307,000	$ 335,001,000
Deferred revenue					42,380,000			$ 42,380,000
Revenue recognized					23,364,000	36,032,000	80,634,000
Deferred revenue, net of current portion					21,474,000	25,345,000		21,474,000
Short-term deferred revenue					20,906,000	15,214,000		20,906,000
Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable					19,094,000	3,045,000	15,822,000	19,094,000
License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue under agreement					71,362,000	166,406,000	223,882,000
Mitsubishi Tanabe Pharma Corporation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue under agreement					800,000	400,000		1,200,000
Mitsubishi Tanabe Pharma Corporation | License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue under agreement					12,438,000	15,405,000	$ 10,000,000
Mitsubishi Tanabe Pharma Corporation | Regulatory Milestone, Approval Of Vadadustat In Japan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue under agreement						15,000,000
Mitsubishi Tanabe Pharma Corporation | Regulatory Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue					$ 25,000,000
Recognized revenue under agreement				$ 10,000,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Collaboration Agreement, Global Phase 3 Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from collaborators	$ 0
Mitsubishi Tanabe Pharma Corporation | MTPC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement, expiration period					10 years
Collaboration agreement, notice period for termination					12 months
Additional milestone or royalty payments received					$ 0
Number of performance obligations | performance_obligation					2
Deferred revenue					$ 7,469,000			7,469,000
Deferred revenue, net of current portion					0			0
Short-term deferred revenue					$ 7,469,000			7,469,000
Mitsubishi Tanabe Pharma Corporation | MTPC | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty payments on sales					20.00%
Mitsubishi Tanabe Pharma Corporation | MTPC | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty payments on sales					13.00%
Mitsubishi Tanabe Pharma Corporation | MTPC | Regulatory Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue		$ 15,000,000			$ 25,000,000
Mitsubishi Tanabe Pharma Corporation | MTPC | Regulatory Milestone Payments | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received					40,000,000
Mitsubishi Tanabe Pharma Corporation | MTPC | Development, Regulatory and Commercial Events | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone revenue					225,000,000
Mitsubishi Tanabe Pharma Corporation | MTPC | Development Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue					10,000,000
Mitsubishi Tanabe Pharma Corporation | MTPC | Commercial Milestone Payments | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone revenue (up to)		$ 175,000,000
Mitsubishi Tanabe Pharma Corporation | Development And Commercialize Research And License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received					20,000,000
Incurred clinical and commercial development cost					20,500,000
Cost of research services					20,500,000
Accounts receivable					0			0
Deferred revenue					0			0
Mitsubishi Tanabe Pharma Corporation | Development And Commercialize Research And License Agreement | Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable					200,000			200,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received			$ 10,400,000
Revenue recognized					0	$ 6,200,000
Deferred revenue, net of current portion					0			0
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited | Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable					0			0
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited | Other Current Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Short-term deferred revenue					2,100,000			2,100,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited | Other Noncurrent Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, net of current portion					0			0
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Supply Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized					11,600,000
Up front payments invoiced					18,200,000			18,200,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Supply Agreement [Member] | Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up front payments invoiced					9,400,000			9,400,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Supply Agreement [Member] | Other Current Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up front payments invoiced					14,900,000			14,900,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Supply Agreement [Member] | Other Noncurrent Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up front payments invoiced					5,800,000			5,800,000
Mitsubishi Tanabe Pharma Corporation | Mitsubishi Tanabe Pharma Corporation Supply Agreement [Member] | Contract With Customer, Liability
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up front payments invoiced					$ 7,500,000			$ 7,500,000