Cash, Cash Equivalents and Short-Term Investments (Details 1) $ in Thousands	May 31, 2019 USD ($) securities	Nov. 30, 2018 USD ($) securities
Schedule of Available-for-sale Securities
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	$ 185,696	$ 551,404
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	976,725	1,020,199
Available-for-sale securities, continuous unrealized loss position, less than 12 months, accumulated loss	(43)	(8,101)
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, accumulated loss	$ (3,693)	$ (17,272)
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | securities	58	369
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | securities	547	577
Asset-backed securities
Schedule of Available-for-sale Securities
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	$ 5,501	$ 6,696
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	24,847	34,812
Available-for-sale securities, continuous unrealized loss position, less than 12 months, accumulated loss	0	(54)
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, accumulated loss	(80)	(313)
Corporate debt securities
Schedule of Available-for-sale Securities
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	178,253	538,109
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	940,760	969,701
Available-for-sale securities, continuous unrealized loss position, less than 12 months, accumulated loss	(43)	(7,966)
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, accumulated loss	(3,581)	(16,730)
Municipal securities
Schedule of Available-for-sale Securities
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	1,942	6,599
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	8,725	11,532
Available-for-sale securities, continuous unrealized loss position, less than 12 months, accumulated loss	0	(81)
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, accumulated loss	(26)	(205)
Foreign government securities
Schedule of Available-for-sale Securities
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	2,393	4,154
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, accumulated loss	$ (6)	$ (24)