4. Investments (Tables)

6 Months Ended

Jun. 30, 2018

Investments Schedule [Abstract]

Investments, Held-to-Maturity Securities

	Gross Unrealized
	Level		Cost		Gains		Losses			Fair Value
As of June 30, 2018:
Short-term Investments
Certificates of deposit		2		2,021	$	--	$	(4	)	$	2,017
Commercial paper		2		10,977	$	--	$	(9	)	$	10,968
Bonds		2		11,178	$	--	$	(29	)	$	11,149
Long-term Investments
Bonds		2		18,781	$	--	$	(259	)	$	18,522
Mutual funds		1		485	$	--	$	(4	)	$	481
Equity investments		2		5,675	$	--	$	(2,729	)	$	2,946
As of December 31, 2017:
Short-term Investments
Certificates of deposit		2		4,020	$	--	$	(3	)	$	4,017
Commercial paper		2		31,220	$	26	$	(38	)	$	31,208
Bonds		2		6	$	--	$	--		$	6
Mutual funds		1		219	$	3	$	--		$	222
Long-term Investments
Bonds		2		5,000	$	--	$	(75	)	$	4,925
Equity investments		2		5,675	$	--	$	(1,539	)	$	4,136