Accrued Expenses and Other Current Liabilities

3 Months Ended

12 Months Ended

Mar. 31, 2018

Dec. 31, 2017

Payables and Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

4. Accrued Expenses and Other Current Liabilities

	March 31, 2018		December 31, 2017
Accrued external research and development expenses	$	2,567	$	1,770
Accrued payroll and related expenses		600		1,369
Accrued professional fees		824		878
Accrued other		493		304
	$	4,484	$	4,321

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):

	December 31,
	2017		2016
Accrued external research and development expenses	$	1,770	$	627
Accrued payroll and related expenses		1,369		1,018
Accrued professional fees		878		1,062
Accrued other		304		221
	$	4,321	$	2,928