Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of available-for-sale securities

The amortized cost and fair value of investments in fixed maturities classified as available-for-sale as of December 31, 2021 and December 31, 2020 are presented below (in thousands):

	As of December 31, 2021
	Amortized Cost		ACL¹		Unrealized Gain		Unrealized Loss		Estimated Fair Value
Marketable securities - restricted
Corporate debt securities	$	2,547	$	—	$	—	$	(2)	$	2,545
U.S. treasury and agency securities	35,385		—		—		(104)		35,281
Commercial paper	16,081		—		—		—		16,081
Asset backed securities	8,728		—		—		(10)		8,718
Total marketable securities - restricted	$	62,741	$	—	$	—	$	(116)	$	62,625

¹ Represents the ACL recorded following the adoption of accounting guidance for credit losses on January 1, 2021. For further information refer to Note 1, Basis of Presentation and Significant Accounting Policies.

	As of December 31, 2020
	Amortized Cost		Unrealized Gain		Unrealized Loss		Estimated Fair Value
Marketable securities - restricted
Corporate debt securities	$	5,938	$	17	$	—	$	5,955
U.S. treasury securities	6,994		—		—		6,994
Commercial paper	8,791		—		—		8,791
Asset backed securities	2,911		—		—		2,911
Total marketable securities - restricted	$	24,634	$	17	$	—	$	24,651

Schedule of amortized cost and estimated fair value of marketable securities

The amortized cost and estimated fair value of marketable securities as of December 31, 2021 and December 31, 2020 and are shown below by contractual maturity (in thousands):

	As of December 31, 2021
	Amortized Cost		Estimated Fair Value
Due within one year	$	41,603	$	41,596
Due between one to five years	21,138		21,029
	$	62,741	$	62,625

	As of December 31, 2020
	Amortized Cost		Estimated Fair Value
Due within one year	$	21,603	$	21,629
Due between one to five years	3,031		3,022
	$	24,634	$	24,651

Schedule of unrealized loss on investments

The following table summarizes, for all fixed maturities classified as available-for-sale in an unrealized loss position at December 31, 2021, the aggregate fair value and gross unrealized loss by length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in Note 2, Fair Value. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in Note 1, Basis of Presentation and Significant Accounting Policies in determining whether a credit loss impairment exists.

	As of December 31, 2021
	Less Than 12 Months				12 Months or Longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Marketable securities - restricted
Corporate debt securities	$	737	$	(2)	$	—	$	—	$	737	$	(2)
U.S. treasury and agency securities	31,809		(104)		—		—		31,809		(104)
Commercial paper	1,808		—		—		—		1,808		—
Asset backed securities	8,716		(10)		—		—		8,716		(10)
Total in an unrealized loss position	$	43,070	$	(116)	$	—	$	—	$	43,070	$	(116)

	As of December 31, 2020
	Less Than 12 Months				12 Months or Longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Marketable securities - restricted
Corporate debt securities	$	2,826	$	—	$	—	$	—	$	2,826	$	—
U.S. treasury and agency securities	1,016		—		—		—		1,016		—
Commercial paper	—		—		—		—		—		—
Asset backed securities	593		—		—		—		593		—
Total in an unrealized loss position	$	4,435	$	—	$	—	$	—	$	4,435	$	—