Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale and Equity 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 September 30, 2018 and December 31, 2017, respectively:

	September 30, 2018
Marketable Securities:	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value
Equity securities	$	10,068	$	77	$	(209	)	$	9,936
Money market funds	41,350		200		—			41,550
Corporate bonds	33,266		6		(236		)	33,036
Government securities - U.S.	13,756		—		(200		)	13,556
Other fixed-income securities	9,361		9		(23		)	9,347
Total	$	107,801	$	292	$	(668	)	$	107,425

	December 31, 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

Schedule of Contractual Maturity Dates

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 September 30, 2018:

	Maturities
Marketable Debt Securities:	Less than 1 Year		1-5 Years		5-10 Years		Greater than 10 Years		Total
Corporate bonds	$	19,017	$	13,820	$	199	$	—	$	33,036
Government securities - U.S.	831		12,224		—		501		13,556
Other fixed-income securities	51		9,296		—		—		9,347
Total	$	19,899	$	35,340	$	199	$	501	$	55,939