Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Measurements

Summary of financial assets and liabilities measured on recurring basis

	September 30, 2020								December 31, 2019
	Level I		Level II		Level III		Total		Level I		Level II		Level III		Total
	(in thousands)
Financial Assets:
Money market deposits	$	178,894	$	—	$	—	$	178,894	$	22,477	$	—	$	—	$	22,477
U.S. Treasury securities		530,808		—		—		530,808		293,157		—		—		293,157
Municipal securities		—		69,397		—		69,397		—		85,908		—		85,908
Total financial assets	$	709,702	$	69,397	$	—	$	779,099	$	315,634	$	85,908	$	—	$	401,542