Investments (Tables)

12 Months Ended

Dec. 31, 2020

Investments

Schedule of Investments

Investments classified as available-for-sale securities were as follows:

	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

	December 31, 2019
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
Corporate debt securities	$	178	$	—	$	(125)	$	53
		178		—		(125)		53
Restricted investments:
Short-term bond		2,239		11		—		2,250
Money market fund		114		—		—		114
		2,353		11		—		2,364
	$	2,531	$	11	$	(125)	$	2,417

Schedule of Unrealized Loss Position and Related Fair Value of Investments

The following table provides the available-for-sale investments with an unrealized loss position and their related fair values:

	December 31, 2020								December 31, 2019
	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:
Corporate debt securities	$	—	$	—	$	—	$	—	$	—	$	—	$	53	$	125

Schedule of Contractual Maturities of Investments

	December 31, 2020
	Amortized Cost		Fair Value
Due in one year or less	$	48,046	$	48,051
Restricted investments		1,160		1,171
	$	49,206	$	49,222