Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

Financial Instruments

Schedule of available-for-sale securities

	December 31, 2022								December 31, 2021
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)		Estimated Fair Value		Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)		Estimated Fair Value
	(in thousands)
Money market deposits	$	283,358	$	—	$	—	$	283,358	$	10,041	$	—	$	—	$	10,041
Liquid demand deposits		125,596		—		—		125,596		—		—		—		—
U.S. Treasury securities (1)		358,385		—		(12,328)		346,057		689,640		1,081		(2,624)		688,097
Corporate bonds and notes (1)		24,045		—		(516)		23,529		52,729		—		(392)		52,337
Municipal securities		65,973		1		(3,259)		62,715		89,814		261		(613)		89,462
Total	$	857,357	$	1	$	(16,103)	$	841,255	$	842,224	$	1,342	$	(3,629)	$	839,937
Classified as:
Cash equivalents (2)							$	408,954							$	10,041
Short-term investments								432,301								829,896
Total							$	841,255							$	839,937

(1)

Per the Company’s investment policy, all debt securities are classified as short-term investments irrespective of holding period.

(2) Cash equivalents includes cash sweep accounts, liquid demand deposits and U.S. Treasury money market mutual funds.

Schedule of debt securities available-for-sale in unrealized loss position

	Less Than 12 Months				12 Months or Longer				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
	(in thousands)
U.S. Treasury securities	$	18,677	$	(565)	$	327,374	$	(11,762)	$	346,051	$	(12,327)
Corporate bonds and notes		—		—		23,529		(516)		23,529		(516)
Municipal securities		16,371		(127)		44,843		(3,133)		61,214		(3,260)
Total	$	35,048	$	(692)	$	395,746	$	(15,411)	$	430,794	$	(16,103)

Summarized portfolio of available-for-sale securities by contractual maturity

	December 31, 2022
	Amortized Cost		Fair Value
	(in thousands)
Less than or equal to one year	$	329,499	$	320,708
Greater than one year but less than five years		118,904		111,593
Total	$	448,403	$	432,301