Liability Related to Sale of Future Royalties - Summary of Liability Related to Potential Future Royalties (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended		22 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Other Liabilities Disclosure [Abstract]
Liability related to sale of future royalties-beginning balance	$ 131,266
Proceeds from sale of future royalties			124,000
Non-cash interest expense recognized	22,309		40,366
Non-cash CIMZIA®and MIRCERA®royalty revenue	(22,055)	(10,791)	(32,846)
Payments from Nektar to RPI	(3,000)		(3,000)
Total liability related to sale of future royalties as of December 31, 2013	128,520		128,520
Less: current portion	(7,000)	(3,000)	(7,000)
Liability related to sale of future royalties, less current portion	$ 121,520	$ 128,266	$ 121,520