INVESTMENTS: (Tables)

12 Months Ended

Dec. 31, 2012

INVESTMENTS:

Schedule of cash, cash equivalents and short-term investments

	December 31, 2012
	Amortized Cost			Net Unrealized Gains (Losses)			Estimated Fair Value
	(in thousands)
Cash	$	110,148		$	—		$	110,148
Certificates of deposit		90,437			(6	)		90,431
U.S. Government and agency securities		115,179			(50	)		115,129
Commercial paper		34,977			(30	)		34,947
Corporate bonds		61,543			(81	)		61,462
Foreign government bonds		7,511			19			7,530
Total investments in marketable securities	$	419,795		$	(148	)	$	419,647
Less amounts classified as cash and cash equivalents		(117,054	)		—			(117,054	)
	$	302,741		$	(148	)	$	302,593

	December 31, 2011
	Amortized Cost			Net Unrealized Gains (Losses)			Estimated Fair Value
	(in thousands)
Cash	$	71,808		$	—		$	71,808
Money market funds		105,246			—			105,246
Certificates of deposit		50,170			(18	)		50,152
U.S. Government and agency securities		250			1			251
Corporate bonds		5,215			2			5,217
Foreign government bonds		957			0			957
Total investments in marketable securities	$	233,646		$	(15	)	$	233,631
Less amounts classified as cash and cash equivalents		(181,258	)		—			(181,258	)
	$	52,388		$	(15	)	$	52,373

Schedule of contractual maturities of debt securities

	December 31, 2012				December 31, 2011
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in less than one year	$	58,758	$	58,724	$	42,670	$	42,660
Due in one to three years		243,983		243,869		9,718		9,713
	$	302,741	$	302,593	$	52,388	$	52,373