Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale Securities

The following tables show the Company’s available-for-sale securities’ adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category as of December 31, 2018 and 2017, respectively:

	2018
Marketable Securities:	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value
Equity securities	$	10,101	$	—	$	(956	)	$	9,145
Money market funds	52,733		316		(53		)	52,996
Corporate bonds	6,411		7		(79		)	6,339
Government securities - U.S.	12,714		66		(79		)	12,701
Other fixed-income securities	9,400		22		(13		)	9,409
Total	$	91,359	$	411	$	(1,180	)	$	90,590

	2017
Marketable Securities:	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value
Equity securities	$	443	$	31	$	(6	)	$	468
Money market funds	44,525		—		(44		)	44,481
Corporate bonds	9,285		1		(24		)	9,262
Government securities - U.S.	19,080		—		(30		)	19,050
Other fixed-income securities	4,259		—		(9		)	4,250
Total	$	77,592	$	32	$	(113	)	$	77,511

Investments Classified by Contractual Maturity Date

The following table summarizes the estimated fair value of our investments in marketable debt securities, accounted for as available-for-sale securities and classified by the contractual maturity date of the securities as of December 31, 2018:

	Maturities
Marketable Debt Securities:	Less than 1 Year		1-5 Years		5-10 Years		Greater than 10 Years		Total
Corporate bonds	$	1,511	$	4,828	$	—	$	—	$	6,339
Government securities - U.S.	771		11,145		281		504		12,701
Other fixed-income securities	—		9,409		—		—		9,409
Total	$	2,282	$	25,382	$	281	$	504	$	28,449