Carrying amount as of the balance sheet date of obligations due all related parties.

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Other License Agreements - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Sep. 30, 2017	Aug. 31, 2016
Helsinn License Agreement
Related Party Transaction [Line Items]
Compensation receivable for grant of rights		$ 20.0
Presage License Agreement \| Presage Biosciences, Inc.
Related Party Transaction [Line Items]
Compensation payable for grant of rights	$ 4.9
Payment for license	2.9
Presage License Agreement \| Presage Biosciences, Inc. \| Incremental Payment
Related Party Transaction [Line Items]
Compensation payable for grant of rights	2.0
Presage License Agreement \| Presage Biosciences, Inc. \| Potential Payments on Achievement of Development Regulatory and Commercial Milestones
Related Party Transaction [Line Items]
Milestone payment receivable amount	$ 179.0