Collaboration and License Agreements - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 26, 2020	Apr. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2020	Mar. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Increase in contract liability from regulatory milestones achieved					$ 93,897,000
Contract assets			$ 0		0				$ 0
Change in deferred revenue					478,908,000	$ 0
Deferred revenue recognized					33,300,000
Collaboration revenue			1,379,000	$ 0	1,379,000	0
Cost share advance from collaboration partner					138,800,000	0
Richter
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment received included in current deferred revenue									$ 40,000,000.0
Maximum payment from regulatory milestones achieved										$ 40,000,000.0
Increase in contract liability from regulatory milestones achieved		$ 10,000,000.0
Maximum payment from sales-related milestones achieved										$ 107,500,000
Decrease in contract liability from regulatory milestones achieved			0	$ 0	33,300,000	$ 0
Deferred revenue, additions					10,000,000.0
Pfizer
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum payment from regulatory milestones achieved	$ 100,000,000.0
Maximum payment from sales-related milestones achieved	$ 3,500,000,000
Percentage of revenue recognized	100.00%
Upfront payment received	$ 650,000,000.0
Maximum payment from milestones achieved	3,700,000,000
Maximum aggregate payment from milestones achieved	200,000,000.0
Option exercise fee	$ 50,000,000.0
Percent of costs covered by counterparty	100.00%
Proceeds for cost share advance	$ 150,000,000.0
Repayment period	2 years
Reduction in cost share advance from implied financing costs	$ 3,600,000
Cost share advance	146,400,000		$ 138,800,000		138,800,000
Deferred revenue	$ 503,600,000
Deferred revenue, recognition period	6 years
Deferred revenue, additions					503,600,000
Collaboration revenue					1,400,000
Shared costs					7,600,000
Cost share advance from collaboration partner					138,800,000
Amortized deferred financing costs (less than)					$ 100,000
Pfizer | Forecast
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Costs covered by company							$ 50,000,000.0	$ 100,000,000.0