License, Collaboration and Other Significant Agreements - U.S. Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd. Narrative (Details)		1 Months Ended		12 Months Ended			33 Months Ended	60 Months Ended
	Dec. 31, 2016 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2021 USD ($) performance_obligation	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues				$ 213,578,000	$ 295,307,000	$ 335,001,000
Deferred revenue				42,380,000			$ 42,380,000	$ 42,380,000
Short-term deferred revenue				20,906,000	15,214,000		20,906,000	20,906,000
Deferred revenue, net of current portion				21,474,000	25,345,000		21,474,000	21,474,000
Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				3,171,000	7,227,000	0	3,171,000	3,171,000
Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable				4,309,000	1,722,000	0	4,309,000	4,309,000
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	19,094,000
License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues				71,362,000	166,406,000	223,882,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangements cost sharing payments				360,100,000
Collaborative arrangements additional cost sharing payments amount				$ 111,900,000
Percentage of market penetration for license agreement				90.00%
License agreement, notice period for termination				12 months
Number of performance obligations | performance_obligation				3
Transaction price				$ 518,900,000
Reimbursement for Otsuka's share of costs previously incurred	$ 33,800,000
Deferred revenue				20,372,000			20,372,000	20,372,000
Short-term deferred revenue				7,970,000			7,970,000	7,970,000
Deferred revenue, net of current portion				12,402,000			12,402,000	12,402,000
Cost share costs incurred				17,500,000	5,100,000	1,800,000
Reimbursable by Otsuka				8,600,000	2,200,000	700,000
Cost share costs by partner for license agreement				900,000	2,100,000	1,900,000
Reimbursable to Otsuka				400,000	1,100,000	1,000,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				2,000,000			2,000,000	2,000,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable				3,000,000			3,000,000	3,000,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable				0			$ 0	0
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues				$ 36,588,000	$ 93,446,000	$ 131,314,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of increase in funding to fund current global development costs			52.50%
Reduction in percentage of future payments due upon current global development costs creditable				50.00%
Percentage of remaining creditable amount applied to future payments				50.00%
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of increase in funding to fund current global development costs							80.00%
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Global Development Plan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reimbursement for Otsuka's share of costs previously incurred		$ 33,800,000
Collaborative arrangements additional cost sharing payments expected amount				$ 149,600,000
Otsuka Pharmaceutical Co. Ltd. | Otsuka U.S. Agreement | Global Development Plan | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangements cost sharing payments								360,100,000
Otsuka Pharmaceutical Co. Ltd. | Up-front, Non-refundable and Non-creditable | Otsuka U.S. Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received			$ 125,000,000	125,000,000
Otsuka Pharmaceutical Co. Ltd. | Regulatory Milestone Payments | Otsuka U.S. Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential developmental milestone revenue				65,000,000			$ 65,000,000	$ 65,000,000
Otsuka Pharmaceutical Co. Ltd. | Commercial Milestone Payments | Otsuka U.S. Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone revenue (up to)				$ 575,000,000