Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2023

Financial Instruments

Schedule of available-for-sale securities

	March 31, 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	$	246,954	$	—	$	246,954	$	283,358	$	—	$	—	$	283,358
Liquid demand deposits		126,986		—		126,986		125,596		—		—		125,596
U.S. Treasury securities (1)		342,958		(8,554)		334,404		358,385		—		(12,328)		346,057
Corporate bonds and notes (1)		19,014		(295)		18,719		24,045		—		(516)		23,529
Municipal securities		58,388		(2,653)		55,735		65,973		1		(3,259)		62,715
Total	$	794,300	$	(11,502)	$	782,798	$	857,357	$	1	$	(16,103)	$	841,255
Classified as:
Cash equivalents (2)						373,940								408,954
Short-term investments						408,858								432,301
Total					$	782,798							$	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 money market deposits and liquid demand deposits.

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

	Total
	Fair Value		Unrealized Loss
U.S. Treasury securities	$	334,404	$	(8,554)
Corporate bonds and notes		18,719		(295)
Municipal securities		55,735		(2,653)
Total	$	408,858	$	(11,502)

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

	March 31, 2023
	Amortized Cost		Fair Value
	(in thousands)
Less than or equal to one year	$	349,114	$	341,858
Greater than one year but less than five years		71,246		67,000
Total	$	420,360	$	408,858