Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets [Line Items]
Impairment charge			$ 0	$ 599,118,000	$ 198,700,000	$ 0
Indefinite-lived intangible assets		$ 607,548,000	$ 332,199,000	332,199,000	607,548,000
Net gain on sale of intangible assets				$ 0	369,498,000	$ 67,500,000
Medivation
Goodwill And Intangible Assets [Line Items]
Upfront payment received					410,000,000
Milestone payments		160,000,000			$ 160,000,000
IPR&D of Kyndrisa and Other Exon
Goodwill And Intangible Assets [Line Items]
Impairment charge	$ 574,100,000	198,700,000
Indefinite-lived intangible assets	0
IPR&D of Reveglucosidase Alfa
Goodwill And Intangible Assets [Line Items]
Impairment charge	$ 25,000,000
Talazoparib
Goodwill And Intangible Assets [Line Items]
Net gain on sale of intangible assets		$ 369,500,000