Description of Operations and Summary of Significant Accounting Policies - Description, Segments (Details) $ in Millions			12 Months Ended
	Jun. 02, 2014	Jun. 01, 2014 USD ($)	Dec. 31, 2016 USD ($) segment item	Dec. 31, 2015 USD ($)
Description of Operations and Summary of Significant Accounting Policies
Cash, cash equivalents and marketable securities contributed from Innoviva | $		$ 393.0
Economic interest in future payments, number of affiliates | item			1
Common stock dividend ratio	0.286
Basis of presentation
Number of separate cash accounts historically maintained prior to Spin-Off | item			0
Segment reporting
Number of operating segments | segment			1
Restricted Cash
Restricted cash | $			$ 0.8	$ 0.8