Liability Related to Sale of Future Royalties - Additional Information (Detail) (USD $)	3 Months Ended		1 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2013 Milestone Scenario One [Member]	Mar. 31, 2014 Milestone Scenario Two [Member]	Feb. 24, 2012 Purchase and Sale Agreement with RPI [Member]
Liability Related to Sale of Future Royalties [Line Items]
Proceeds from sale of royalty rights					$ 124,000,000
Non-cash royalty revenue	5,773,000	4,393,000
Annual interest rate	17.00%
Payment made for milestone not achieved year one			3,000,000
Payment made for milestone not achieved year two				$ 7,000,000
Royalty agreement contingent payment description	As a result of worldwide net sales of MIRCERA® for the 12 month periods ended on December 31, 2013 and 2012 not reaching certain minimum thresholds.