Marketable Securities (Notes)

3 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Marketable securities as of March 31, 2019 and December 31, 2018 consisted of the following:



March 31, 2019	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money market mutual funds	$	25	$	—	$	—	$	25
Total marketable securities designated as available-for-sale	$	25	$	—	$	—	$	25



December 31, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money market mutual funds	$	25	$	—	$	—	$	25
Total marketable securities designated as available-for-sale	$	25	$	—	$	—	$	25

The amortized costs and fair value of marketable securities as of March 31, 2019 and December 31, 2018 are shown below by effective maturity. Effective maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties.



March 31, 2019	Amortized Cost		Fair Value
Due in less than one year	$	—	$	—
December 31, 2018	Amortized Cost		Fair Value
Due in less than one year	$	—	$	—

Interest income from marketable securities was less than $1 and $12 during the three months ended March 31, 2019 and 2018, respectively.