Investment Securities (Tables)

3 Months Ended

Mar. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Schedule of Investment Securities Reconciliation

The following tables present amortized cost and fair values of investments at March 31, 2023 and December 31, 2022, respectively:

March 31, 2023	Amortized cost		Accumulated unrealized gains		Accumulated unrealized losses		Fair value
	(in thousands)
Investment securities, held-to-maturity
U.S. government and government agencies and authorities	$	756	$	—	$	(90)	$	666
Investment securities, available-for-sale
U.S. government and government agencies and authorities	192,016		60		(6,687)		185,389
Corporate debt securities	106,689		95		(499)		106,285
Total held-to-maturity and available-for-sale investment securities	$	299,461	$	155	$	(7,276)	$	292,340

December 31, 2022	Amortized cost		Accumulated unrealized gains		Accumulated unrealized losses		Fair value
	(in thousands)
Investment securities, held-to-maturity
U.S. government and government agencies and authorities	$	757	$	—	$	(106)	$	651
Investment securities, available-for-sale
U.S. government and government agencies and authorities	237,457		10		(9,000)		228,467
Corporate debt	98,783		38		(422)		98,399
Total held-to-maturity and available-for-sale investment securities	$	336,997	$	48	$	(9,528)	$	327,517

Schedule of Amortized Cost and Fair Value of Debt Securities

The following table presents the amortized cost and fair value of debt securities at March 31, 2023, by contractual maturity:

March 31, 2023	Held-to-maturity				Available-for-sale
	Amortized cost		Fair value		Amortized cost		Fair value
	(in thousands)
Due within one year	$	15	$	15	$	159,062	$	156,542
Due after one year through five years	631		553		139,643		135,132
Due after five years through ten years	—		—		—		—
Due after ten years	110		98		—		—
Total	$	756	$	666	$	298,705	$	291,674

Schedule of Net Investment Income

For the three months ended March 31, 2023 and 2022, respectively, net investment income, which is included within Other income within the Consolidated Statements of Operations and Comprehensive Loss, was derived from the following sources:

	Three Months Ended March 31,
	2023		2022
	(in thousands)
Cash and cash equivalents	$	1,629	$	2
Short-term investments	492		71
Investment securities	1,814		237
Investment income, net	$	3,935	$	310

Schedule of Gross Unrealized Losses and Fair Value for Fixed Maturities in a Continuous Unrealized Loss Position

Gross unrealized losses and fair values aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position were as follows at March 31, 2023, and December 31, 2022, respectively:

March 31, 2023	Less than 12 months				Greater than 12 months				Total
	Fair value		Unrealized loss		Fair value		Unrealized loss		Fair value		Unrealized loss
	(in thousands, except number of positions)
U.S. government and government agencies and authorities	$	11,535	$	(76)	$	155,066	$	(6,701)	$	166,601	$	(6,777)
Corporate debt securities	72,854		(499)		—		—		72,854		(499)
Total	$	84,389	$	(575)	$	155,066	$	(6,701)	$	239,455	$	(7,276)
Number of positions	79				25				104

December 31, 2022	Less than 12 months				Greater than 12 months				Total
	Fair value		Unrealized loss		Fair value		Unrealized loss		Fair value		Unrealized loss
	(in thousands, except number of positions)
U.S. government and government agencies and authorities	$	64,261	$	(958)	$	147,757	$	(8,148)	$	212,018	$	(9,106)
Corporate debt securities	78,292		(422)		—		—		78,292		(422)
Total	$	142,553	$	(1,380)	$	147,757	$	(8,148)	$	290,310	$	(9,528)
Number of positions	92				24				116

Schedule of Realized Gain (Loss) on Investment Securities

Proceeds from sales and maturities of investment securities, inclusive of Short-term investments, and related gross realized gains (losses) which are included within Other income within the Consolidated Statements of Operations and Comprehensive Loss, were as follows for the three months ended March 31, 2023 and 2022, respectively:

	Three Months Ended March 31,
	2023		2022
	(in thousands)
Proceeds from sales of investment securities	$	15,001	$	—
Proceeds from maturities of investment securities	63,324		150,000
Gross realized gains	—		—
Gross realized losses	—		—
Net realized losses	$	—	$	—