License and Collaboration Agreements	12 Months Ended
Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License and Collaboration Agreements	5. License and Collaboration Agreements On April 3, 2017, the Servier Agreement was assigned to Ipsen in connection with the completion of the Ipsen Sale, as discussed in Note 1, “Nature of the Business and Summary of Significant Accounting Policies.” The Company retained the rights to receive net milestone payments that may become payable pursuant to the Servier Agreement for the ex-U.S. development and commercialization of ONIVYDE for up to $33.0 million. For the years ended December 31, 2019 and 2018, the Company received $5.0 million and $28.0 million of milestone payments, respectively.

The entire disclosure for collaborative arrangements in which the entity is a participant, including a) information about the nature and purpose of such arrangements; b) its rights and obligations thereunder; c) the accounting policy for collaborative arrangements; and d) the income statement classification and amounts attributable to transactions arising from the collaborative arrangement between participants.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 808
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6931272&loc=SL5834143-161434

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 808
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6931272&loc=SL5834143-161434

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 808
-URI http://asc.fasb.org/topic&trid=5833765

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