CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS

Cash equivalents consist of instruments with remaining maturities of three months or less at the date of purchase. We classify all of our cash equivalents and short-term investments as “available-for-sale.” In general, these investments are free of trading restrictions. We carry these investments at fair value, based on quoted market prices or other readily available market information. Unrealized gains and losses, net of taxes, are included in accumulated other comprehensive income, which is reflected as a separate component of stockholders’ equity in our condensed consolidated balance sheets. Gains and losses are recognized when realized in our condensed consolidated statements of income. When we have determined that an other-than-temporary decline in fair value has occurred, the amount of the decline that is related to a credit loss is recognized in income. Gains and losses are determined using the specific identification method.

Cash, cash equivalents and short-term investments consisted of the following as of September 1, 2017 (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Current assets:
Cash	$	413,411	$	—	$	—		$	413,411
Cash equivalents:
Money market mutual funds	1,344,350		—		—			1,344,350
Time deposits	16,789		—		—			16,789
Total cash equivalents	1,361,139		—		—			1,361,139
Total cash and cash equivalents	1,774,550		—		—			1,774,550
Short-term fixed income securities:
Asset-backed securities	99,295		51		(162		)	99,184
Corporate bonds and commercial paper	2,427,062		8,962		(3,000		)	2,433,024
Municipal securities	145,850		162		(51		)	145,961
U.S. Treasury securities	917,426		14		(1,673		)	915,767
Total short-term investments	3,589,633		9,189		(4,886		)	3,593,936
Total cash, cash equivalents and short-term investments	$	5,364,183	$	9,189	$	(4,886	)	$	5,368,486

Cash, cash equivalents and short-term investments consisted of the following as of December 2, 2016 (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Current assets:
Cash	$	208,635	$	—	$	—		$	208,635
Cash equivalents:
Corporate bonds and commercial paper	1,249		—		—			1,249
Money market mutual funds	782,210		—		—			782,210
Municipal securities	1,301		—		—			1,301
Time deposits	17,920		—		—			17,920
Total cash equivalents	802,680		—		—			802,680
Total cash and cash equivalents	1,011,315		—		—			1,011,315
Short-term fixed income securities:
Asset-backed securities	111,009		95		(190		)	110,914
Corporate bonds and commercial paper	2,464,769		3,135		(9,554		)	2,458,350
Municipal securities	134,710		37		(525		)	134,222
U.S. agency securities	39,538		42		—			39,580
U.S. Treasury securities	1,008,195		194		(1,470		)	1,006,919
Total short-term investments	3,758,221		3,503		(11,739		)	3,749,985
Total cash, cash equivalents and short-term investments	$	4,769,536	$	3,503	$	(11,739	)	$	4,761,300

See Note 4 for further information regarding the fair value of our financial instruments.

The following table summarizes the fair value and gross unrealized losses related to available-for-sale securities, aggregated by investment category, that have been in an unrealized loss position for less than twelve months, as of September 1, 2017 and December 2, 2016 (in thousands):



	2017					2016
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds and commercial paper	$	710,735	$	(2,497	)	$	1,282,076	$	(9,474	)
Asset-backed securities	62,235		(150		)	54,063		(189		)
Municipal securities	6,387		(23		)	114,810		(525		)
U.S. Treasury and agency securities	808,221		(1,400		)	580,529		(1,470		)
Total	$	1,587,578	$	(4,070	)	$	2,031,478	$	(11,658	)

There were 570 securities and 1,052 securities in an unrealized loss position for less than twelve months at September 1, 2017 and at December 2, 2016, respectively.

The following table summarizes the fair value and gross unrealized losses related to available-for-sale securities, aggregated by investment category, that were in a continuous unrealized loss position for more than twelve months, as of September 1, 2017 and December 2, 2016 (in thousands):



	2017					2016
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds and commercial paper	$	94,397	$	(503	)	$	39,162	$	(80	)
Asset-backed securities	1,495		(12		)	1,331		(1		)
Municipal securities	10,077		(28		)	—		—
U.S. Treasury and agency securities	47,636		(273		)	—		—
Total	$	153,605	$	(816	)	$	40,493	$	(81	)

There were 90 securities and 23 securities in an unrealized loss position for more than twelve months at September 1, 2017 and at December 2, 2016, respectively.

The following table summarizes the cost and estimated fair value of short-term fixed income securities classified as short-term investments based on stated effective maturities as of September 1, 2017 (in thousands):



	Amortized Cost		Estimated Fair Value
Due within one year	$	1,079,772	$	1,079,092
Due between one and two years	1,353,653		1,353,378
Due between two and three years	776,048		778,726
Due after three years	380,160		382,740
Total	$	3,589,633	$	3,593,936

We review our debt and marketable equity securities classified as short-term investments on a regular basis to evaluate whether or not any security has experienced an other-than-temporary decline in fair value. We consider factors such as the length of time and extent to which the market value has been less than the cost, the financial condition and near-term prospects of the issuer and our intent to sell, or whether it is more likely than not we will be required to sell the investment before recovery of the investment’s amortized cost basis. If we believe that an other-than-temporary decline exists in one of these securities, we write down these investments to fair value. For debt securities, the portion of the write-down related to credit loss would be recorded to interest and other income, net in our condensed consolidated statements of income. Any portion not related to credit loss would be recorded to accumulated other comprehensive income, which is reflected as a separate component of stockholders’ equity in our condensed consolidated balance sheets. For equity securities, the write-down would be recorded to investment gains (losses), net in our condensed consolidated statements of income. During the nine months ended September 1, 2017 and September 2, 2016, we did not consider any of our investments to be other-than-temporarily impaired.