License, Collaboration and Other Significant Agreements - U.S. Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd. (Details)		3 Months Ended
	Dec. 31, 2016 USD ($)	Mar. 31, 2022 USD ($) performance_obligation	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Apr. 01, 2019	Mar. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		$ 61,699,000	$ 52,304,000
Deferred revenue		75,796,000
Short-term deferred revenue		10,440,000		$ 20,906,000
Deferred revenue, net of current portion		65,356,000		21,474,000
Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		24,316,000	3,539,000	19,094,000	$ 3,045,000
Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		3,970,000	1,916,000	4,309,000	1,722,000
Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue		319,000	0	3,171,000	$ 7,227,000
License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		$ 20,251,000	21,896,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations | performance_obligation		3
Percentage of costs funded by customer						80.00%	52.50%
Collaborative arrangements additional cost sharing payments amount		$ 117,400,000
Transaction price		514,400,000
Reimbursement of costs	$ 33,800,000
Collaborative arrangements cost sharing payments		355,600,000
Deferred revenue		22,279,000
Short-term deferred revenue		6,192,000
Deferred revenue, net of current portion		16,087,000
Cost share costs incurred		7,600,000	1,000,000
Reimbursable costs		3,800,000	500,000
Cost share costs by partner for license agreement		0	300,000
Costs reimbursed			200,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Global Development Plan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangements additional cost sharing payments expected amount		$ 149,600,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reduction in percentage of future payments due upon current global development costs creditable		50.00%
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of remaining creditable amount applied to future payments		50.00%
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		$ 9,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		2,700,000		3,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				$ 2,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		5,638,000	$ 13,674,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | HIF Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)		65,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Licensed Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)		575,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Up Front Non Refundable And Non Creditable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received		125,000,000
Otsuka Pharmaceutical Company. Ltd. | Otsuka U.S. Agreement | Development And Regulatory Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue		$ 0