Collaboration and License Agreements - Schedule of Contract Assets and Liabilities and Changes in Contract Balances (Parenthetical) (Detail) $ in Millions	Mar. 31, 2018 USD ($)
Accounting Standards Update 2014-09 [Member] \| Accumulated Deficit [Member]
Contract with Customer, Asset and Liability [Line Items]
Cumulative effect of adoption to opening balance of accumulated deficit	$ 47.3

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

No definition available.

Name:	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant