Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Measurements

Summary of financial assets and liabilities measured on recurring basis

	June 30, 2019								December 31, 2018
	Level I		Level II		Level III		Total		Level I		Level II		Level III		Total
	(in thousands)
Financial Assets:
Money market deposits	$	630	$	—	$	—	$	630	$	26,539	$	—	$	—	$	26,539
U.S. Treasury securities		159,097		—		—		159,097		75,685		—		—		75,685
U.S. agency securities		—		12,977		—		12,977		—		12,891		—		12,891
Municipal securities		—		35,979		—		35,979		—		18,885		—		18,885
Total financial assets	$	159,727	$	48,956	$	—	$	208,683	$	102,224	$	31,776	$	—	$	134,000