Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2025

Fair Value Disclosures [Abstract]

Summary of Investments

Investments consist of the following as of March 31, 2025 and December 31, 2024 (dollars in thousands):

	March 31, 2025
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available-for-sale):
Non-governmental debt securities	$	242,291	$	588	$	(70	)	$	242,809
Treasury and federal agencies		215,396		382		(60	)		215,718
Total short-term investments (available-for-sale)	$	457,687	$	970	$	(130	)	$	458,527

	December 31, 2024
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available-for-sale):
Non-governmental debt securities		246,070		466		(278	)		246,258
Treasury and federal agencies		213,394		258		(115	)		213,537
Total short-term investments (available-for-sale)	$	459,464	$	724	$	(393	)	$	459,795

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

Financial instruments measured at fair value on a recurring basis subject to the disclosure requirements of FASB ASC Topic 820 - Fair Value Measurements at March 31, 2025 and December 31, 2024 were as follows (dollars in thousands):

	As of March 31, 2025
	Level 1		Level 2		Total
Cash and cash equivalents - money market funds	$	30,745	$	-	$	30,745
Short-term investments - non-governmental debt securities		-		242,809		242,809
Short-term investments - treasury and federal agencies		-		215,718		215,718
Totals	$	30,745	$	458,527	$	489,272
	As of December 31, 2024
	Level 1		Level 2		Total
Cash and cash equivalents - money market funds	$	30,189	$	-	$	30,189
Cash and cash equivalents - federal agency debt securities		-		13,078		13,078
Short-term investments - non-governmental debt securities		-		246,258		246,258
Short-term investments - treasury and federal agencies		-		213,537		213,537
Totals	$	30,189	$	472,873	$	503,062

Schedule of Maintenance Fee Payment to our equity affiliate

We make periodic operating maintenance payments to an equity affiliate. The total fees recorded during the quarters ended March 31, 2025 and 2024 were as follows (dollars in thousands):

	Maintenance Fee Payments
For the quarter ended March 31, 2025	$	428
For the quarter ended March 31, 2024	$	444