Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended			15 Months Ended
	Apr. 30, 2015	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2016
Liability Related to Sale of Future Royalties
Royalty revenue				$ 195		$ (23)	$ 5,099	$ 4,625	$ 4,166	$ 195	$ 13,867	$ 10,346
Transaction costs for royalty agreements										5,865
Movement in Deferred Revenue [Roll Forward]
Proceeds from sale of future royalties											194,135
Non-cash Kadcyla royalty revenue		$ (5,944)	$ (7,380)	(6,291)	$ (5,684)	(5,484)				(25,299)	(5,484)
Non-cash interest expense on liability related to sale of future royalties and convertible senior notes		4,956	$ 4,972	$ 5,059	5,143	5,437				20,130	5,437
Kadcyla
Liability Related to Sale of Future Royalties
Percentage of royalty payments if applicable threshold is met	85.00%
Kadcyla | IRH
Liability Related to Sale of Future Royalties
Percentage of royalty payments	100.00%
Royalty revenue	$ 235,000
Royalties on net sales of Kadcyla when royalties to the purchaser reach a specified milestone	$ 260,000
Percentage of royalty payments if applicable threshold is met	15.00%
Transaction costs for royalty agreements	$ 5,900
Movement in Deferred Revenue [Roll Forward]
Liability related to sale of future royalties — beginning balance					$ 199,662					199,662
Proceeds from sale of future royalties													$ 200,000
Non-cash Kadcyla royalty revenue										(25,299)			(30,783)
Non-cash interest expense on liability related to sale of future royalties and convertible senior notes										19,009			24,155
Liability related to sale of future royalties — ending balance		$ 193,372				$ 199,662				$ 193,372	$ 199,662		$ 193,372
Effective annual interest rate													9.60%