Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended									1 Months Ended	3 Months Ended				22 Months Ended		3 Months Ended	1 Months Ended	36 Months Ended	3 Months Ended	36 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	1 Months Ended		3 Months Ended	1 Months Ended
	Sep. 30, 2013 item	Sep. 30, 2013 Development and Commercialization License item	Sep. 30, 2012 Development and Commercialization License	Sep. 30, 2013 Development and Commercialization License Minimum	Sep. 30, 2013 Development and Commercialization License Maximum	Sep. 30, 2013 Development and Commercialization License Kadcyla Minimum	Sep. 30, 2013 Development and Commercialization License Kadcyla Maximum	Sep. 30, 2013 Right-to-Test Agreements Minimum	Sep. 30, 2013 Right-to-Test Agreements Maximum	Oct. 31, 2013 Amgen Subsequent event item	Sep. 30, 2013 Amgen Exclusive development and commercialization license item	Sep. 30, 2013 Amgen Non-exclusive development and commercialization license item	Sep. 30, 2013 Bayer HealthCare Exclusive development and commercialization license item	Sep. 30, 2013 Biotest Exclusive development and commercialization license item	Sep. 30, 2013 Lilly	Sep. 30, 2013 Lilly Development and Commercialization License	Sep. 30, 2013 Lilly Exclusive development and commercialization license item	Dec. 31, 2011 Lilly Right-to-Test Agreements	Sep. 30, 2013 Novartis	Sep. 30, 2013 Novartis Development and Commercialization License item	Sep. 30, 2013 Novartis Development and Commercialization License	Mar. 29, 2013 Novartis Exclusive development and commercialization license item	Sep. 30, 2013 Novartis Exclusive development and commercialization license item	Mar. 29, 2013 Novartis Right-to-Test Agreements	Oct. 31, 2010 Novartis Right-to-Test Agreements	Oct. 31, 2013 Novartis Right-to-Test Agreements Subsequent event	Sep. 30, 2013 Roche Exclusive development and commercialization license item	May 31, 2000 Roche Exclusive development and commercialization license Kadcyla
Summary of Significant Accounting Policies
Term of agreement																		3 years							3 years	3 years
Term of extension of agreement																									1 year	1 year
Payments for extension of agreement																										$ 5,000,000
Payments received for the second license															28,200,000	23,500,000		20,000,000	55,200,000		55,400,000			1,000,000	45,000,000	1,000,000		2,000,000
Number of non-exclusive license agreements converted to an exclusive license agreement										1
Payments received under collaboration agreement in connection with amended agreement										500,000														3,500,000
Number of types of licensing and development agreements with collaborative partners	2
Number of single-target licenses											3	1	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	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		$ 0	$ 755,000
Number of types of milestone payments under collaborative arrangements		3
Average period over which upfront payments are deferred and recognized								12 months	18 months