Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended													0 Months Ended	12 Months Ended
	Jun. 30, 2013 item	Jun. 30, 2013 Development and Commercialization License item	Jun. 30, 2012 Development and Commercialization License	Jun. 30, 2011 Development and Commercialization License	Jun. 30, 2013 Development and Commercialization License Minimum	Jun. 30, 2013 Development and Commercialization License Maximum	Jun. 30, 2013 Right-to-Test Agreements Minimum	Jun. 30, 2013 Right-to-Test Agreements Maximum	Jun. 30, 2013 Amgen Exclusive development and commercialization license item	Jun. 30, 2013 Amgen Non-exclusive development and commercialization license item	Jun. 30, 2013 Bayer HealthCare Exclusive development and commercialization license item	Jun. 30, 2013 Biotest Exclusive development and commercialization license item	Jun. 30, 2013 Novartis Development and Commercialization License item	Mar. 29, 2013 Novartis Exclusive development and commercialization license item	Jun. 30, 2013 Novartis Exclusive development and commercialization license item	Jun. 30, 2013 Roche Exclusive development and commercialization license item
Revenue Recognition
Number of types of licensing and development agreements with collaborative partners	2
Number of single-target licenses									3	1	1	1		1	1	5
Number of licenses to two related targets													1
Number of related targets													2
Period after product launch in which the company will earn royalty payments					10 years	12 years
T-DM1 royalty term on a country-by-country basis					10 years	12 years
Average involvement period over which the upfront payments on single-target licenses are amortized		6 years 6 months
Difference between the full cost to manufacture and amounts received from collaborators for preclinical and clinical materials		$ 755,000	$ 85,000	$ 1,300,000
Number of types of milestone payments under collaborative arrangements		3
Average period over which upfront payments are deferred and recognized							12 months	18 months