Accrued Expenses (Tables)

9 Months Ended

Sep. 30, 2017

Payables And Accruals [Abstract]

Summary of Accrued Expenses

Accrued expenses consist of the following:

	September 30, 2017		December 31, 2016
	(in thousands)
Development costs	$	27,326	$	14,541
Employee-related expenses		6,299		5,948
Professional services		3,179		1,751
Other accrued expenses		3		112
	$	36,807	$	22,352