License and Collaboration Agreements - License, Collaboration and Other Revenue (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	$ 6,476	$ 7,827
Roche [Member] | PEGASYS and MIRCERA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	2,625	1,380
Amgen, Inc. [Member] | Neulasta [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	1,285	1,250
Bayer Healthcare LLC [Member] | BAY41-6551 (Amikacin Inhale) [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	714	742
Baxter Healthcare [Member] | Hemophilia [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	700	684
Affymax, Inc. [Member] | Omontys [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	177	2,217
Other [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, collaboration, and other revenue	$ 975	$ 1,554