Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2023

Financial Instruments

Schedule of available-for-sale securities

	June 30, 2023						December 31, 2022
	Amortized Cost		Gross Unrealized Loss		Estimated Fair Value		Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
	(in thousands)
Money market deposits	$	216,337	$	—	$	216,337	$	283,358	$	—	$	—	$	283,358
Liquid demand deposits		128,562		—		128,562		125,596		—		—		125,596
U.S. Treasury securities (1)		302,590		(6,100)		296,490		358,385		—		(12,328)		346,057
Corporate bonds and notes (1)		9,002		(101)		8,901		24,045		—		(516)		23,529
Municipal securities		52,105		(2,668)		49,437		65,973		1		(3,259)		62,715
Total	$	708,596	$	(8,869)	$	699,727	$	857,357	$	1	$	(16,103)	$	841,255
Classified as:
Cash equivalents (2)						344,899								408,954
Short-term investments						354,828								432,301
Total					$	699,727							$	841,255

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

(2) Cash equivalents includes restricted cash, money market deposits and liquid demand deposits.

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

	Total
	Fair Value		Unrealized Loss
	(in thousands)
U.S. Treasury securities	$	296,490	$	(6,100)
Corporate bonds and notes		8,901		(101)
Municipal securities		46,429		(2,668)
Total	$	351,820	$	(8,869)

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

	June 30, 2023
	Amortized Cost		Fair Value
	(in thousands)
Less than or equal to one year	$	296,067	$	291,495
Greater than one year but less than five years		67,630		63,333
Total	$	363,697	$	354,828