INVESTMENTS: (Details) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 27, 2015 item	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Amortized Cost
Total		$ 463,709		$ 463,709		$ 385,876
Less amounts classified as cash and cash equivalents		(68,203)		(68,203)		(51,326)
Short term investments, amortized cost		395,506		395,506		334,550
Unrealized Gains (Losses)
Total unrealized gains				107		29
Total unrealized losses				(269)		(541)
Estimated Fair Value
Total		463,547		463,547		385,364
Less amounts classified as cash and cash equivalents		(68,203)		(68,203)		(51,326)
Short-term investments classified as available-for-sale securities		395,344		395,344		334,038
Realized gains (losses), net upon the sale of marketable securities		2,100	$ 500	2,400	$ 900
Amortized cost
Due in less than one year		190,743		190,743		129,150
Due in one to three years		204,759		204,759		205,400
Amortized cost		395,502		395,502		334,550
Estimated fair value
Due in less than one year		190,745		190,745		129,155
Due in one to three years		204,599		204,599		204,883
Estimated fair value		395,344		395,344		334,038
Restricted cash and deposits
Restricted cash		3,604		3,604		3,604
Investment in a privately-held companies accounted for under the cost method		7,700		7,700		10,700
Number of privately-held companies impaired | item	1
Investment in privately-held company was impaired and the impairment of this investment was other than temporary				3,189
Other current assets
Restricted cash and deposits
Carrying value of privately-held company with discontinued operations						200
Other long term assets
Restricted cash and deposits
Carrying value of privately-held company with discontinued operations						3,000
Cash
Amortized Cost
Total		61,580		61,580		46,900
Estimated Fair Value
Total		61,580		61,580		46,900
Money market funds
Amortized Cost
Total		6,623		6,623		4,426
Estimated Fair Value
Total		6,623		6,623		4,426
Certificates of deposits
Amortized Cost
Total		103,884		103,884		80,304
Unrealized Gains (Losses)
Unrealized Gains		12		12		1
Unrealized Losses		(1)		(1)		(30)
Estimated Fair Value
Total		103,895		103,895		80,275
U.S. Government and agency securities
Amortized Cost
Total		62,588		62,588		99,236
Unrealized Gains (Losses)
Unrealized Gains		34		34		9
Unrealized Losses		(12)		(12)		(131)
Estimated Fair Value
Total		62,610		62,610		99,114
Commercial paper
Amortized Cost
Total		59,620		59,620		23,017
Unrealized Gains (Losses)
Unrealized Gains		17		17		3
Unrealized Losses		(2)		(2)		(1)
Estimated Fair Value
Total		59,635		59,635		23,019
Corporate bonds
Amortized Cost
Total		127,156		127,156		112,033
Unrealized Gains (Losses)
Unrealized Gains		36		36		16
Unrealized Losses		(174)		(174)		(313)
Estimated Fair Value
Total		127,018		127,018		111,736
Municipal bonds
Amortized Cost
Total		28,137		28,137		13,151
Unrealized Gains (Losses)
Unrealized Gains		6		6
Unrealized Losses		(53)		(53)		(47)
Estimated Fair Value
Total		28,090		28,090		13,104
Foreign government bonds
Amortized Cost
Total		14,121		14,121		6,809
Unrealized Gains (Losses)
Unrealized Gains		2		2
Unrealized Losses		(27)		(27)		(19)
Estimated Fair Value
Total		$ 14,096		$ 14,096		$ 6,790