Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Product revenue related reserves	$ 45,249	$ 26,146
Accrued employee compensation costs	43,240	24,692
Accrued contract manufacturing costs	27,622	15,794
Accrued milestone expense	18,390	24,020
Accrued clinical and pre-clinical costs	18,010	11,396
Accrued professional fees	10,707	11,319
Accrued collaboration cost-sharing	9,000	2,167
Accrued royalties	6,301	8,254
Other	7,008	10,307
Total accrued expenses	$ 185,527	$ 134,095