Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Measurements

Summary of financial assets and liabilities measured on recurring basis

	December 31, 2021								December 31, 2020
	Level I		Level II		Level III		Total		Level I		Level II		Level III		Total
	(in thousands)
Financial Assets:
Money market deposits	$	10,041	$	—	$	—	$	10,041	$	28,990	$	—	$	—	$	28,990
U.S. Treasury securities		688,097		—		—		688,097		597,744		—		—		597,744
Corporate bonds and notes		—		52,337		—		52,337		—		12,328		—		12,328
Municipal securities		—		89,462		—		89,462		—		78,534		—		78,534
Total financial assets	$	698,138	$	141,799	$	—	$	839,937	$	626,734	$	90,862	$	—	$	717,596