INVESTMENTS: (Tables)

6 Months Ended

Jun. 30, 2015

INVESTMENTS:

Schedule of cash, cash equivalents and short-term investments

	June 30, 2015
	Amortized			Unrealized		Unrealized			Estimated
	Cost			Gains		Losses			Fair Value
	(in thousands)
Cash	$	61,580		$	—	$	—		$	61,580
Money market funds	6,623			—		—			6,623
Certificates of deposit	103,884			12		(1		)	103,895
U.S. Government and agency securities	62,588			34		(12		)	62,610
Commercial paper	59,620			17		(2		)	59,635
Corporate bonds	127,156			36		(174		)	127,018
Municipal bonds	28,137			6		(53		)	28,090
Foreign government bonds	14,121			2		(27		)	14,096
Total	$	463,709		$	107	$	(269	)	$	463,547
Less amounts classified as cash and cash equivalents	(68,203		)	—		—			(68,203		)
	$	395,506		$	107	$	(269	)	$	395,344

	December 31, 2014
	Amortized Cost			Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	46,900		$	—	$	—		$	46,900
Money market funds	4,426			—		—			4,426
Certificates of deposit	80,304			1		(30		)	80,275
U.S. Government and agency securities	99,236			9		(131		)	99,114
Commercial paper	23,017			3		(1		)	23,019
Corporate bonds	112,033			16		(313		)	111,736
Municipal bonds	13,151			—		(47		)	13,104
Foreign government bonds	6,809			—		(19		)	6,790
Total	$	385,876		$	29	$	(541	)	$	385,364
Less amounts classified as cash and cash equivalents	(51,326		)	—		—			(51,326		)
	$	334,550		$	29	$	(541	)	$	334,038

Schedule of contractual maturities of short-term investments

	June 30, 2015				December 31, 2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in less than one year	$	190,743	$	190,745	$	129,150	$	129,155
Due in one to three years	204,759		204,599		205,400		204,883
	$	395,502	$	395,344	$	334,550	$	334,038