Agreements (Details) (Roche, USD $)	1 Months Ended			146 Months Ended	1 Months Ended				1 Months Ended
	May 31, 2000 Development, Manufacturing and Commercialization	May 31, 2000 Development, Manufacturing and Commercialization Maximum	May 31, 2000 Development, Manufacturing and Commercialization Regulatory milestones	Jun. 30, 2012 Development, Manufacturing and Commercialization T-DM1 Development milestones	Jul. 31, 2007 Development, Manufacturing and Commercialization T-DM1 Development milestones Phase II clinical trial	Feb. 28, 2009 Development, Manufacturing and Commercialization T-DM1 Development milestones Phase III clinical trial	May 31, 2000 Development, Manufacturing and Commercialization T-DM1 Regulatory milestones in U.S.	May 31, 2000 Development, Manufacturing and Commercialization T-DM1 Regulatory milestones in Europe	May 31, 2000 Right-to-test agreement Undisclosed Target item	May 31, 2000 Right-to-test agreement Undisclosed Target Maximum	May 31, 2000 Right-to-test agreement Undisclosed Target Development milestones	May 31, 2000 Right-to-test agreement Undisclosed Target Regulatory milestones	May 31, 2000 Right-to-test agreement Undisclosed Target Sales milestones	Jun. 30, 2012 Right-to-test agreement Undisclosed Target IND application filed
Collaborative Agreements disclosures
Payments received under collaboration agreement	$ 2,000,000			$ 13,500,000	$ 5,000,000	$ 6,500,000
License exercise fee, per license									1,000,000
Potential milestone payments receivable		44,000,000	30,500,000				10,500,000	5,000,000		38,000,000	8,000,000	20,000,000	10,000,000	1,000,000
Number of undisclosed targets with exclusive licenses									4
Payment received and deferred									$ 5,000,000
Term of agreement									8 years