Liability Related to Sale of Future Royalties - Additional Information (Detail) (USD $)	3 Months Ended		1 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Feb. 24, 2012
Liability Related to Sale of Future Royalties [Line Items]
Non-cash royalty revenue	$ 3,962,000	$ 5,773,000
Annual interest rate	17.00%
Royalty agreement contingent payment description	As a result of worldwide net sales of MIRCERAfor the 12 month periods ended December 31, 2013 and 2012 not reaching certain minimum thresholds.
Milestone Scenario One [Member]
Liability Related to Sale of Future Royalties [Line Items]
Payment made for milestone not achieved year one			3,000,000
Milestone Scenario Two [Member]
Liability Related to Sale of Future Royalties [Line Items]
Payment made for milestone not achieved year two				7,000,000
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