Investment Securities (Tables)

6 Months Ended

Jun. 30, 2018

Investments Debt And Equity Securities [Abstract]

Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Estimated Fair Values of Fixed-Maturity Securities

The amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of total fixed-maturity securities and total fixed-maturity securities held in trust at December 31, 2017, are as follows:

	December 31, 2017
Class of securities:	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. government sponsored enterprises	$	2,249	$	—	$	(10	)	$	2,239
Corporate debt securities		1,425		—		(4	)		1,421
Total fixed-maturity securities		3,674		—		(14	)		3,660
Less total unrestricted fixed-maturity securities		2,151		—		(9	)		2,142
Total fixed-maturity securities held in trust	$	1,523	$	—	$	(5	)	$	1,518

Summary of Net Investment Income

Net investment income for the three and six months ended June 30, 2018 and 2017, respectively, is summarized as follows:

	Three months ended June 30, 2018			Three months ended June 30, 2017			Six months ended June 30, 2018			Six months ended June 30, 2017
Investment income:
Amortization of premium or discount on fixed-maturity securities	$	(6	)	$	(45	)	$	(13	)	$	(76	)
Investment income on fixed-maturity securities		1			153			18			331
Interest income on cash and cash equivalents		2,878			1,618			5,149			2,632
Realized gain (loss) from sale of investments		6			(25	)		2			(27	)
Unrealized gain on cash equivalents held at period end		163			—			58			—
Unrealized gain on trading securities held at period end		17			2			15			23
Net investment income	$	3,059		$	1,703		$	5,229		$	2,883

Schedule of Investments in Accordance with Fair Value Measurement

The following table shows how the Company’s investments are categorized in accordance with fair value measurement, as of June 30, 2018:

	June 30, 2018
	Level 1		Level 2		Level 3		Total
Money market funds		28,684		—		—		28,684
Total	$	28,684	$	—	$	—	$	28,684

The following table shows how the Company’s investments are categorized in accordance with fair value measurement, as of December 31, 2017:

	December 31, 2017
	Level 1		Level 2		Level 3		Total
Class of securities:
Obligations of U.S. government sponsored enterprises		995		1,244		—		2,239
Corporate debt securities		1,421		—		—		1,421
Total fixed-maturity securities		2,416		1,244		—		3,660
Money market funds		30,780		—		—		30,780
Total	$	33,196	$	1,244	$	—	$	34,440

Summary of Transfers between Level 1 and Level 2

	January 1, 2018 to June 30, 2018				January 1, 2017 to  December 31, 2017
	Transfers from Level 1 to Level 2		Transfers from Level 2 to Level 1			Transfers from Level 1 to Level 2		Transfers from Level 2 to Level 1
Class of securities:
Obligations of US government sponsored enterprises	$	—	$	—		$	—	$	995
Corporate debt securities		—		—			—		1,421
Total transfers	$	—	$	—		$	—	$	2,416