Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Measurements [Abstract]

Schedule of fair value measurement on a recurring basis

December 31, 2017

	Carrying amount in				Fair Value Measurement Using
	balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Commercial paper	$	568	$	568	$	568	$	0	$	0
Treasury bills		7,711		7,711		7,711		0		0
Equity securities		45		45		0		0		45
Liabilities:
Contingent earn-out		150		150		0		0		150

December 31, 2016

	Carrying amount in				Fair Value Measurement Using
	balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Commercial paper	$	348	$	348	$	348	$	0	$	0
Treasury bills		7,427		7,427		7,427		0		0
Equity securities		0		0		0		0		0
Liabilities:
Contingent earn-out		195		195		0		0		195

Summary of changes in level 3 assets at fair value on a recurring basis

	Years Ended December 31,
	2017		2016
Beginning Balance	$	0	$	0
Increase in value		45		0
Ending Balance	$	45	$	0

Schedule of change in level 3 liabilities at fair value on a recurring basis

	Years Ended December 31,
	2017			2016
Beginning Balance	$	195		$	455
Credit to Earnings		(45	)		(260	)
Ending Balance	$	150		$	195