5.	Investments in Marketable Securities

Amortized cost and fair value of marketable securities, available-for-sale, by type of security consisted of the following (in thousands):

 

		December 31, 2017																December 31, 2016
		Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Fair Value				Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Fair Value
Short-term investments:
U.S. treasuries		$	57,712			$	—			$	(88	)		$	57,624			$	24,987			$	—			$	(30	)		$	24,957
U.S. government sponsored entities			7,016				—				(8	)			7,008				2,497				—				—				2,497
Corporate debt securities			8,931				—				(3	)			8,928				—				—				—				—
		$	73,659			$	—			$	(99	)		$	73,560			$	27,484			$	—			$	(30	)		$	27,454
Long-term investments:
U.S. treasuries		$	18,111			$	7			$	(164	)		$	17,954			$	40,865			$	—			$	(229	)		$	40,636
U.S. government sponsored entities			5,306				—				(62	)			5,244				12,618				—				(58	)			12,560
Corporate debt securities			22,505				268				(54	)			22,719				17,841				74				(165	)			17,750
Asset-backed securities and other			6,180				17				(15	)			6,182				6,557				18				(46	)			6,529
		$	52,102			$	292			$	(295	)		$	52,099			$	77,881			$	92			$	(498	)		$	77,475

The amortized cost and fair value of the Company’s investments in available-for-sale securities that have been in a continuous unrealized loss position consisted of the following (in thousands):

 

		December 31, 2017								December 31, 2016
		Unrealized Loss				Fair Value				Unrealized Loss				Fair Value
Less than 12 months		$	(158	)		$	63,229			$	(491	)		$	86,105
12 months or longer		$	(236	)		$	44,961			$	(37	)		$	721

Gross realized gains and gross realized losses from the sales of the Company’s available-for-sale securities consisted of the following (in thousands):

 

		December 31,
		2017				2016
Gross realized gains (1)		$	2			$	43
Gross realized losses (1)		$	—			$	(166	)

 

(1)	Recorded in other income (expense), net in the consolidated statements of net and comprehensive income. The cost basis of securities sold were determined on the specific identification method.

 

The Company may sell certain of its marketable securities, available-for-sale prior to their stated maturities for strategic reasons including, but not limited to, anticipated liquidity and capital requirements, anticipated credit deterioration, duration management or when a security no longer meets the criteria of the Company’s investment policy. During 2016, the Company sold one security, which no longer met the requirements of its investment policy for a loss of $152,000.

As of December 31, 2017, the Company considers the declines in market value of its marketable securities, available-for-sale to be temporary in nature and does not consider any of its investments other-than-temporarily impaired. The Company typically invests in highly-rated securities, and its investment policy generally limits the amount of credit exposure to any one issuer. The policy generally requires investments to be investment grade, with the primary objective of minimizing the potential risk of principal loss and matching long-term liabilities. When evaluating an investment for other-than-temporary impairment the Company reviews factors such as the length of time and extent to which fair value has been below its cost basis, the financial condition of the issuer and any changes thereto, changes in market interest rates and the Company’s intent to sell, or whether it is more likely than not it will be required to sell the investment before recovery of the investment’s cost basis. The Company has no current intent to sell and it is not more likely than not that the Company will be required to sell these investments before recovery of their amortized cost basis, which may be at maturity. The Company may sell certain of its marketable securities, available-for-sale prior to their stated maturities for strategic reasons including, but not limited to, anticipated liquidity and capital requirements, anticipated credit deterioration, duration management or when a security no longer meets the criteria of the Company’s investment policy.

Amortized cost and fair value of marketable securities, available-for-sale, by contractual maturity consisted of the following (in thousands):

 

		December 31, 2017								December 31, 2016
		Amortized Cost				Fair Value				Amortized Cost				Fair Value
Due in one year or less		$	73,659			$	73,560			$	27,484			$	27,454
Due after one year through five years			30,644				30,517				57,309				57,144
Due after five years through ten years			15,090				15,200				14,992				14,841
Due after ten years			6,368				6,382				5,580				5,490
		$	125,761			$	125,659			$	105,365			$	104,929
Weighted average maturity			2.6 years								3.5 years

Actual maturities may differ from contractual maturities because certain borrowers are required to make principal payments or have the right to prepay certain obligations with or without prepayment penalties.