Cash, Cash Equivalents, and Investments

Cash, cash equivalents, and investments consisted of the following (in thousands):



	July 1, 2018		December 31, 2017
Cash	$	124,147	$	97,951
Money market instruments	5,055		8,631
Cash and cash equivalents	129,202		106,582
Treasury bills	136,377		150,371
Corporate bonds	116,347		47,395
Asset-backed securities	55,240		59,203
Agency bonds	29,247		10,608
Municipal bonds	9,154		8,805
Sovereign bonds	7,375		21,579
Short-term investments	353,740		297,961
Corporate bonds	208,454		296,014
Asset-backed securities	47,740		71,727
Sovereign bonds	8,971		13,147
Agency bonds	5,934		14,890
Municipal bonds	842		4,204
Treasury bills	—		23,459
Long-term investments	271,941		423,441
	$	754,883	$	827,984

Treasury bills consist of debt securities issued by the U.S. government; corporate bonds consist of debt securities issued by both domestic and foreign companies; asset-backed securities consist of debt securities collateralized by pools of receivables or loans with credit enhancement; agency bonds consist of domestic or foreign obligations of government agencies and government sponsored enterprises that have government backing; municipal bonds consist of debt securities issued by state and local government entities; and sovereign bonds consist of direct debt issued by foreign governments. All securities are denominated in U.S. Dollars.

The following table summarizes the Company’s available-for-sale investments as of July 1, 2018 (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Short-term:
Treasury bills	$	136,706	$	3	$	(332	)	136,377
Corporate bonds	116,659		59		(371		)	116,347
Asset-backed securities	55,459		—		(219		)	55,240
Agency bonds	29,248		—		(1		)	29,247
Municipal bonds	9,165		—		(11		)	9,154
Sovereign bonds	7,400		1		(26		)	7,375
Long-term:
Corporate bonds	208,382		636		(564		)	208,454
Asset-backed securities	48,033		12		(305		)	47,740
Sovereign bonds	8,977		35		(41		)	8,971
Agency bonds	5,930		4		—			5,934
Municipal bonds	855		—		(13		)	842
	$	626,814	$	750	$	(1,883	)	$	625,681

The following table summarizes the Company’s gross unrealized losses and fair values for available-for-sale investments in an unrealized loss position as of July 1, 2018 (in thousands):



	Unrealized Loss Position For:
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds	$	139,225	$	(713	)	$	22,908	$	(222	)	$	162,133	$	(935	)
Treasury bills	84,309		(149		)	48,464		(183		)	132,773		(332		)
Asset-backed securities	90,411		(496		)	4,462		(28		)	94,873		(524		)
Agency bonds	29,246		(1		)	—		—			29,246		(1		)
Sovereign bonds	3,562		(9		)	4,581		(58		)	8,143		(67		)
Municipal bonds	3,692		(24		)	—		—			3,692		(24		)
	$	350,445	$	(1,392	)	$	80,415	$	(491	)	$	430,860	$	(1,883	)

As of July 1, 2018, the Company did not recognize any other-than-temporary impairment of these investments. In its evaluation, management considered the type of security, the credit rating of the security, the length of time the security has been in a loss position, the size of the loss position, the Company's intent and ability to hold the security to expected recovery of value, and other meaningful information. The Company does not intend to sell, and is unlikely to be required to sell, any of these available-for-sale investments before their effective maturity or market price recovery.

The Company recorded gross realized gains and gross realized losses on the sale of debt securities totaling $308,000 and $61,000, respectively, during the three-month period ended July 1, 2018 and $55,000 and $13,000, respectively, during the three-month period ended July 2, 2017. The Company recorded gross realized gains and gross realized losses on the sale of debt securities totaling $363,000 and $94,000, respectively, during the six-month period ended July 1, 2018 and $143,000 and $36,000, respectively, during the six-month period ended July 2, 2017. These gains and losses are included in "Investment income" on the Consolidated Statement of Operations. Prior to the sale of these securities, unrealized gains and losses for these debt securities, net of tax, are recorded in shareholders’ equity as accumulated other comprehensive income (loss).

The following table presents the effective maturity dates of the Company’s available-for-sale investments as of July 1, 2018 (in thousands):



	<1 year		1-2 Years		2-3 Years		3-4 Years		4-5 Years		5-7 Years		Total
Corporate bonds	$	116,347	$	96,004	$	71,890	$	29,491	$	7,704	$	3,365	$	324,801
Treasury bills	136,377		—		—		—		—		—		136,377
Asset-backed securities	55,240		31,023		2,178		4,320		5,809		4,410		102,980
Agency bonds	29,247		—		—		—		5,934		—		35,181
Sovereign bonds	7,375		5,963		3,008		—		—		—		16,346
Municipal bonds	9,154		—		842		—		—		—		9,996
	$	353,740	$	132,990	$	77,918	$	33,811	$	19,447	$	7,775	$	625,681