Investments (Tables)

9 Months Ended

Sep. 30, 2019

Investments

Schedule of Investments

	September 30, 2019
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
Corporate debt securities	$	178	$	—	$	(143)	$	35
		178		—		(143)		35
Restricted investments:
Short-term bond		2,229		11		—		2,240
Money market fund		113		—		—		113
		2,342		11		—		2,353
	$	2,520	$	11	$	(143)	$	2,388

	December 31, 2018
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
U.S. Treasury securities	$	6,936	$	1	$	—	$	6,937
Corporate debt securities		2,908		—		(887)		2,021
		9,844		1		(887)		8,958
Restricted investments:
Short-term bond		3,274		—		(9)		3,265
Money market fund		167		—		—		167
		3,441		—		(9)		3,432
	$	13,285	$	1	$	(896)	$	12,390

Schedule of Unrealized Loss Position and Related Fair Value of Investments

	September 30, 2019
	Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
Corporate debt securities	$	—	$	—	$	35	$	143

	December 31, 2018
	Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
Corporate debt securities	$	—	$	—	$	1,843	$	887
Restricted investments:
Short-term bond		—		—		3,265		9
	$	—	$	—	$	5,108	$	896

Schedule of Contractual Maturities of Investments

	September 30, 2019
	Amortized Cost		Fair Value
Due in one year or less	$	178	$	35
Restricted investments		2,342		2,353
	$	2,520	$	2,388