Investments (Tables)

6 Months Ended

Jun. 30, 2021

Investments

Schedule of Investments

	June 30, 2021
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
U.S. Treasury Bills	$	109,974	$	4	$	(3)	$	109,975

	December 31, 2020
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
U.S. Treasury Bills	$	47,986	$	5	$	—	$	47,991
Corporate debt securities		60		—		—		60
		48,046		5		—		48,051
Restricted investments:
Short-term bond		1,160		11		—		1,171
		1,160		11		—		1,171
	$	49,206	$	16	$	—	$	49,222

Schedule of Unrealized Loss Position and Related Fair Value of Investments

	June 30, 2021								December 31, 2020
	Less Than 12 Months				12 Months or Greater				Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
U.S. Treasury Bills	$	75,987	$	3	$	—	$	—	$	—	$	—	$	—	$	—

Schedule of Contractual Maturities of Investments

	June 30, 2021
	Amortized Cost		Fair Value
Due in one year or less	$	109,974	$	109,975