Marketable Securities (Tables)

3 Months Ended

Mar. 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 March 31, 2018 and December 31, 2017, respectively:

	March 31, 2018
Marketable Securities:	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value
Equity securities	$	10,461	$	28	$	(326	)	$	10,163
Money market funds	60,073		—		(14		)	60,059
Corporate bonds	41,554		4		(244		)	41,314
Government securities - U.S.	36,868		40		(131		)	36,777
Other fixed-income securities	8,984		2		(30		)	8,956
Total	$	157,940	$	74	$	(745	)	$	157,269

	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 March 31, 2018:

	Maturities
Marketable Debt Securities:	Less than 1 Year		1-5 Years		5-10 Years		Greater than 10 Years		Total
Corporate bonds	$	18,502	$	22,812	$	—	$	—	$	41,314
Government securities - U.S.	—		36,271		506		—		36,777
Other fixed-income securities	1,207		7,749		—		—		8,956
Total	$	19,709	$	66,832	$	506	$	—	$	87,047