ACCRUED EXPENSES (Tables)

9 Months Ended

Sep. 30, 2018

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 September 30, 2018		As of December 31, 2017
	(in thousands)
Accrued employee compensation costs	$	21,915	$	14,402
Product revenue related reserves		21,684		7,302
Accrued clinical and pre-clinical costs		13,778		15,975
Accrued professional fees		9,112		6,794
Accrued contract manufacturing costs		8,348		14,019
Accrued BioMarin royalties		4,002		2,846
Accrued interest expense		3,183		1,291
Accrued property and equipment		2,515		2,525
Accrued research costs		2,506		401
Accrued collaboration cost sharing		1,200		—
Accrued income taxes		—		943
Other		444		2,484
Total accrued expenses	$	88,687	$	68,982