Cash, Cash Equivalents and Short-Term Investments (Tables)

9 Months Ended

Aug. 31, 2018

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Cash Cash Equivalents and Short term Investments

Cash, cash equivalents and short-term investments consisted of the following as of August 31, 2018 (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Current assets:
Cash	$	386,927	$	—	$	—		$	386,927
Cash equivalents:
Corporate debt securities	24,012		—		(1		)	24,011
Money market mutual funds	1,302,801		—		—			1,302,801
Time deposits	33,405		—		—			33,405
Total cash equivalents	1,360,218		—		(1		)	1,360,217
Total cash and cash equivalents	1,747,145		—		(1		)	1,747,144
Short-term fixed income securities:
Asset-backed securities	77,393		2		(385		)	77,010
Corporate debt securities	2,471,739		614		(20,590		)	2,451,763
Foreign government securities	4,178		—		(29		)	4,149
Municipal securities	19,223		—		(306		)	18,917
U.S. Treasury securities	645,487		—		—			645,487
Total short-term investments	3,218,020		616		(21,310		)	3,197,326
Total cash, cash equivalents and short-term investments	$	4,965,165	$	616	$	(21,311	)	$	4,944,470

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



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Current assets:
Cash	$	280,488	$	—	$	—		$	280,488
Cash equivalents:
Money market mutual funds	2,006,741		—		—			2,006,741
Time deposits	18,843		—		—			18,843
Total cash equivalents	2,025,584		—		—			2,025,584
Total cash and cash equivalents	2,306,072		—		—			2,306,072
Short-term fixed income securities:
Asset-backed securities	98,403		1		(403		)	98,001
Corporate debt securities	2,461,691		2,694		(10,125		)	2,454,260
Foreign government securities	2,396		—		(8		)	2,388
Municipal securities	21,189		8		(132		)	21,065
U.S. Treasury securities	941,538		2		(3,552		)	937,988
Total short-term investments	3,525,217		2,705		(14,220		)	3,513,702
Total cash, cash equivalents and short-term investments	$	5,831,289	$	2,705	$	(14,220	)	$	5,819,774

Continuous Unrealized Loss Position Less Than Twelve Months Related to Available-for-Sale Securities

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 August 31, 2018 and December 1, 2017 (in thousands):



	2018					2017
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate debt securities	$	1,218,367	$	(16,414	)	$	1,338,232	$	(5,459	)
Asset-backed securities	28,820		(240		)	64,618		(193		)
Municipal securities	17,975		(281		)	11,805		(115		)
Foreign government securities	4,149		(29		)	2,388		(8		)
U.S. Treasury securities	—		—			593,296		(2,087		)
Total	$	1,269,311	$	(16,964	)	$	2,010,339	$	(7,862	)

Continuous Unrealized Loss Position Twelve Months or Longer Related to Available-for-Sale-Securities

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 August 31, 2018 and December 1, 2017 (in thousands):



	2018					2017
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate debt securities	$	312,698	$	(4,176	)	$	500,689	$	(4,666	)
Asset-backed securities	17,560		(145		)	32,383		(210		)
Municipal securities	942		(25		)	598		(17		)
U.S. Treasury securities	—		—			338,950		(1,465		)
Total	$	331,200	$	(4,346	)	$	872,620	$	(6,358	)

Cost and Estimated Fair Value of Debt Securities

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 August 31, 2018 (in thousands):



	Amortized Cost		Estimated Fair Value
Due within one year	$	1,643,049	$	1,640,836
Due between one and two years	788,794		782,312
Due between two and three years	608,978		600,690
Due after three years	177,199		173,488
Total	$	3,218,020	$	3,197,326