Marketable Securities (Tables)

6 Months Ended

Jun. 30, 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 June 30, 2018 and December 31, 2017, respectively:

	June 30, 2018
Marketable Securities:	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value
Equity securities	$	10,498	$	35	$	(221	)	$	10,312
Money market funds	66,343		87		—			66,430
Corporate bonds	35,271		7		(240		)	35,038
Government securities - U.S.	15,027		5		(133		)	14,899
Other fixed-income securities	7,970		4		(24		)	7,950
Total	$	135,109	$	138	$	(618	)	$	134,629

	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 June 30, 2018:

	Maturities
Marketable Debt Securities:	Less than 1 Year		1-5 Years		5-10 Years		Greater than 10 Years		Total
Corporate bonds	$	20,673	$	14,365	$	—	$	—	$	35,038
Government securities - U.S.	—		13,909		—		990		14,899
Other fixed-income securities	51		7,899		—		—		7,950
Total	$	20,724	$	36,173	$	—	$	990	$	57,887