Fair Value Measurements - Fair Value Measurement Activity for Liabilities Utilize Level 3 Inputs (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
December 31, 2015	$ 21,352	$ 23,127
Settlement of Ligand Contingent Consideration liability (see Note 9(b))	(6,000)
September 30, 2016	16,075	21,352
Deferred development costs [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Increase/decrease	(526)	(1,099)
Ligand Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Increase/decrease	773	326
Talon CVR [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Increase/decrease	$ 476	$ (1,002)