ACCRUED EXPENSES (Tables)

3 Months Ended

Mar. 31, 2019

Payables And Accruals [Abstract]

Summary of Accrued Expenses

The following table summarizes the Company’s accrued expenses for each of the periods indicated: 

	As of March 31, 2019		As of December 31, 2018
	(in thousands)
Product revenue related reserves	$	29,054	$	26,146
Accrued contract manufacturing costs		16,369		15,794
Accrued employee compensation costs		14,763		24,692
Accrued clinical and pre-clinical costs		12,041		11,396
Accrued professional fees		8,000		11,319
Accrued BioMarin royalties		4,455		8,254
Accrued interest expense		3,183		1,045
Accrued property and equipment		2,878		5,421
Accrued collaboration cost sharing		2,458		2,167
Accrued research costs		1,815		1,070
Accrued milestone expense		1,517		24,020
Other		3,587		2,771
Total accrued expenses	$	100,120	$	134,095