Marketable Securities Marketable Securities

9 Months Ended

Sep. 30, 2018

Marketable Securities [Abstract]

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

Marketable Securities

Marketable securities as of September 30, 2018 and December 31, 2017 consisted of the following:

September 30, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money market mutual funds	$	336	$	—	$	—	$	336
Total marketable securities designated as available-for-sale	$	336	$	—	$	—	$	336

December 31, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Money market mutual funds	$	7,318	$	—	$	—		$	7,318
Certificates of deposit	1,002		—		(1		)	1,001
Total marketable securities designated as available-for-sale	$	8,320	$	—	$	(1	)	$	8,319

The amortized costs and fair value of marketable securities as of September 30, 2018 and December 31, 2017 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.

September 30, 2018	Amortized Cost		Fair Value
Due in less than one year	$	—	$	—
December 31, 2017	Amortized Cost		Fair Value
Due in less than one year	$	1,002	$	1,001

Interest income from marketable securities was $2 and $25 during the three months ended September 30, 2018 and 2017,