Development, Commercialization and Supply Agreement - Additional Information (Detail)	1 Months Ended				3 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Mar. 31, 2016 USD ($)	Feb. 28, 2015 USD ($)	Mar. 31, 2019 USD ($) Item	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
License And Collaboration Agreements [Line Items]
Revenue recognized related to upfront and milestone payments					$ 547,000
Licenses revenue					73,278,000	$ 43,919,000
Deferred revenue					20,163,000		$ 20,710,000
Licensing Revenue
License And Collaboration Agreements [Line Items]
Licenses revenue					$ 547,000	142,000
Mochida | In-licenses | Research and Development Expense
License And Collaboration Agreements [Line Items]
Upfront payment							2,700,000
Eddingpharm | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable up-front received				$ 15,000,000
Number of indications of the regulatory milestone events relating to the submission and approval | Item					3
Amounts to be received upon achievement of the regulatory milestone events					$ 33,000,000
Sales-based milestone event payment					120,000,000
Deferred revenue					13,100,000		13,200,000
Eddingpharm | Out-licenses | Licensing Revenue
License And Collaboration Agreements [Line Items]
Licenses revenue					2,900,000		2,800,000
Eddingpharm | Out-licenses | Maximum
License And Collaboration Agreements [Line Items]
Additional upfront payment eligible to receive based on development, regulatory and sales Milestone					153,000,000
Amounts to be received upon achievement of the regulatory milestone events					15,000,000
Sales-based milestone event payment					50,000,000
Revenue recognized related to upfront and milestone payments					100,000	100,000
Eddingpharm | Out-licenses | Minimum
License And Collaboration Agreements [Line Items]
Amounts to be received upon achievement of the regulatory milestone events					2,000,000
Sales-based milestone event payment					5,000,000
Eddingpharm | Out-licenses | Clinical Trial Application
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment			$ 1,000,000
Biologix FZCo | Out-licenses
License And Collaboration Agreements [Line Items]
Revenue recognition period of non-refundable up-front payment			10 years
HLS | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable up-front received		$ 5,000,000
Non-refundable milestone payment	$ 2,500,000	$ 2,500,000
Revenue recognized related to upfront and milestone payments					400,000	$ 100,000
Deferred revenue					6,200,000		6,600,000
Non-refundable up-front received period		6 months
HLS | Out-licenses | Licensing Revenue
License And Collaboration Agreements [Line Items]
Licenses revenue					$ 1,300,000		$ 900,000
HLS | Out-licenses | Maximum
License And Collaboration Agreements [Line Items]
Additional upfront payment eligible to receive based on development, regulatory and sales Milestone		$ 57,500,000