Collaborative Agreements - Bayer (Details) - Bayer HealthCare - USD ($) $ in Millions	1 Months Ended		6 Months Ended
	Jan. 31, 2016	Oct. 31, 2008	Dec. 31, 2015
Exclusive license
Collaborative Agreements disclosures
Payments received under collaboration agreement		$ 4.0	$ 3.0
Potential milestone payments		170.5
Exclusive license | Development milestones
Collaborative Agreements disclosures
Potential milestone payments		16.0	2.0
Exclusive license | Regulatory milestones
Collaborative Agreements disclosures
Potential milestone payments		44.5	$ 6.0
Exclusive license | Sales milestones
Collaborative Agreements disclosures
Potential milestone payments		$ 110.0
Subsequent event | Development milestones | Phase II clinical trial | Anetumab Ravtansine
Collaborative Agreements disclosures
Payments received under collaboration agreement	$ 10.0