Liability Related to the Sale of Future Royalties - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Feb. 24, 2012	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Liability Related to the Sale of Future Royalties [Line Items]
Non-cash royalty revenue related to sale of future royalties		$ 6,638	$ 8,115	$ 13,301	$ 14,650
Non-cash interest expense on liability related to sale of future royalties		$ 4,512	$ 4,982	$ 9,064	$ 10,027
Annual interest rate				17.00%
Purchase and Sale Agreement with RPI [Member]
Liability Related to the Sale of Future Royalties [Line Items]
Proceeds from sale of royalty rights	$ 124,000
Transaction costs related to sale of potential future royalties	$ 4,400