Collaboration and License Agreements - General Information (Details) - Collaborative Arrangement $ in Millions			1 Months Ended		2 Months Ended	3 Months Ended	12 Months Ended		18 Months Ended
	Oct. 15, 2019 USD ($)	Jun. 01, 2018 USD ($) item	Jul. 31, 2020 USD ($)	Mar. 31, 2016 USD ($) item	Dec. 31, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($)	Nov. 08, 2021 USD ($)	Jul. 13, 2020
Zai Lab (Shanghai) Co., Ltd.
Collaboration Agreements
Collaborative arrangement, upfront payment, cash payment received					$ 25.0
Collaborative arrangement, milestones, contingent payments eligible to receive										$ 590.0
Collaborative arrangement, termination, counterparty written notice period, period from effective date							2 years
Collaborative arrangement, termination, counterparty written notice period, period from effective date, given after first commercial sale of licensed product in counterparty territory							12 months
Collaborative arrangement, termination, counterparty written notice period, period from effective date, given prior to first commercial sale of licensed product in counterparty territory							9 months
Roche, Collaboration (Pralsetnib) Agreement
Collaboration Agreements
Collaborative arrangement, upfront payment, cash payment received						$ 675.0
Collaborative arrangement, milestones, contingent payments eligible to receive					822.0		$ 822.0		$ 822.0
Collaborative arrangement, milestones, specified regulatory and commercialization milestones, achieved							50.0	$ 55.0	105.0
Collaborative arrangement, percentage of global development costs shared, entity (as a percent)											45.00%
Collaborative arrangement, percentage of global development costs shared, counterparty (as a percent)											55.00%
Roche, Collaboration and License (Immunotherapy) Agreement
Collaboration Agreements
Collaborative arrangement, upfront payment, cash payment received				$ 45.0
Collaborative arrangement, option fees and milestones, pre-clinical and clinical development events prior to licensing, contingent payments eligible to receive					319.3		319.3		319.3
Collaborative arrangement, milestones, research milestones, achieved					23.5		$ 23.5		23.5
Collaborative arrangement, license option rights, number | item				5			5
Collaborative arrangement, collaboration programs, number | item							2
Collaborative arrangement, collaboration programs, licensed products, commercialization rights, counterparty exercises option, counterparty receives worldwide exclusivity, number | item				1
Collaborative arrangement, collaboration programs, licensed products, commercialization rights, counterparty exercises option, entity retains domestic and counterparty receives international, number | item							1
Collaborative arrangement, termination, counterparty written notice period				120 days
Collaborative arrangement, termination, counterparty written notice period, after option exercise, if licensed products have not been commercially sold				120 days
Collaborative arrangement, termination, counterparty written notice period, after option exercise, if licensed products have been commercially sold				180 days
Clementia
Collaboration Agreements
Collaborative arrangement, upfront payment, cash payment received	$ 25.0
Collaborative arrangement, milestones, cash payments received			$ 20.0			$ 20.0
Collaborative arrangement, milestones, contingent payments eligible to receive	490.0
Collaborative arrangement, inventory purchased by counterparty	$ 1.5
Collaborative arrangement, termination, counterparty written notice period	12 months
C Stone
Collaboration Agreements
Collaborative arrangement, upfront payment, cash payment received		$ 40.0
Collaborative arrangement, milestones, cash payments received							$ 23.0
Collaborative arrangement, milestones, contingent payments eligible to receive					323.0		323.0		323.0
Collaborative arrangement, milestones, development and regulatory milestones, contingent payments eligible to receive					95.5		95.5		95.5
Collaborative arrangement, milestones, sales-based milestones, contingent payments eligible to receive					$ 227.5		$ 227.5		$ 227.5
Collaborative arrangement, licensed product term from first commercial sale		12 years
Collaborative arrangement, license option rights, number | item		3
Collaborative arrangement, collaboration programs with exclusive commercialization rights, number | item		3