ACCRUED EXPENSES (Tables)

12 Months Ended

Dec. 31, 2017

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 December 31, 2017		As of December 31, 2016
	(in thousands)
Accrued clinical and preclinical costs	$	15,975	$	10,033
Accrued employee compensation costs		14,402		8,748
Accrued contract manufacturing costs		14,019		4,673
Product revenue related reserves		7,302		305
Accrued professional fees		6,794		2,799
Accrued BioMarin royalties		2,846		—
Accrued property and equipment		2,525		1,186
Accrued interest expenses		1,291		100
Accrued income taxes		943		—
Accrued research costs		401		1,186
Other		2,484		1,986
Total accrued expenses	$	68,982	$	31,016