Liability Related to the Sale of Future Royalties - Summary of Liability Related to Potential Future Royalties (Detail) - USD ($) $ in Thousands	12 Months Ended			46 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Liability related to the sale of future royalties—beginning balance	$ 120,471			$ 0
Proceeds from sale of future royalties				124,000
Payments from Nektar to RPI				(10,000)
Non-cash CIMZIA® and MIRCERA® royalty revenue	(22,058)	$ (21,937)	$ (22,055)	(76,841)
Non-cash interest expense recognized	20,619	20,888	$ 22,309	81,873
Liability related to the sale of future royalties – ending balance	$ 119,032	$ 120,471		$ 119,032