Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Measurements

Schedule of Company's assets and liabilities by level within the fair value hierarchy

	March 31, 2018
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds, U.S. Government Securities and Agency Investments	$	124,987	$	—	$	—	$	124,987

	December 31, 2017
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds, U.S. Government Securities and Agency Investments	$	116,433	$	—	$	—	$	116,433