Marketable Securities and Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2013

Short-Term And Long-Term Marketable Securities

Our short-term and long-term marketable securities as of March 31, 2013 and December 31, 2012 are as follows (in thousands):

Short-term

March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds	27,145		21		(2		)	27,164
U.S. dollar dominated foreign corporate bonds	8,052		10		—			8,062
Commercial paper	2,749		—		—			2,749
Total	$	37,946	$	31	$	(2	)	$	37,975

Long-term

March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds	$	7,592	$	2	$	(4	)	$	7,590
U.S. government agency bonds	2,066		2		—			2,068
U.S. dollar dominated foreign corporate bonds	1,023		—		(1		)	1,022
Total	$	10,681	$	4	$	(5	)	$	10,680

Short-term

December 31, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds	$	18,767	$	7	$	(4	)	$	18,770
Commercial paper	4,646		1		—			4,647
U.S. dollar dominated foreign corporate bonds	5,060		9		(1		)	5,068
Total	$	28,473	$	17	$	(5	)	$	28,485

Long-term

December 31, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate bonds	16,132		16		(7		)	16,141
U.S. government agency bonds	$	2,069	$	1	$	—		$	2,070
U.S. dollar dominated foreign corporate bonds	3,038		4		(1		)	3,041
Total	$	21,239	$	21	$	(8	)	$	21,252

Investments Classified by Contractual Maturity Date [Table Text Block]

	March 31,		December 31,
	2013		2012
	(in thousands)		(in thousands)
One year or less	$	37,975	$	28,485
One year through two years	10,680		21,252
Total available for sale securities	$	48,655	$	49,737

Financial Assets Measured At Fair Value On Recurring Basis

The following table summarizes our financial assets measured at fair value on a recurring basis as of March 31, 2013 (in thousands):

Description	Balance as of March 31, 2013		Quoted Prices in Active  Markets for Identical Assets (Level 1)		Significant Other Observable  Inputs (Level 2)
Cash equivalents:
Money market funds	$	258,819	$	258,819	$	—
Commercial paper	500		—		500
Short-term investments:
Commercial paper	2,749		—		2,749
Corporate bonds	27,164		—		27,164
U.S. dollar dominated foreign corporate bonds	8,062		—		8,062
Long-term investments:
Corporate bonds	7,590		—		7,590
U.S. government agency bonds	2,068		—		2,068
U.S. dollar dominated foreign corporate bonds	1,022		—		1,022
Other assets:
Israeli severance funds	2,265		—		2,265
	$	310,239	$	258,819	$	51,420

The following table summarizes our financial assets measured at fair value on a recurring basis as of December 31, 2012 (in thousands):

Description	Balance as of December 31, 2012		Quoted Prices in Active  Markets for Identical Assets (Level 1)		Significant Other Observable  Inputs (Level 2)
Cash equivalents:
Money market funds	$	86,166	$	86,166	$	—
Commercial paper	950		—		950
Short-term investments:
Commercial paper	4,647		—		4,647
Corporate bonds	18,770		—		18,770
U.S. government agency bonds	5,068		—		5,068
Long-term investments:
U.S. government agency bonds	2,070		—		2,070
Corporate bonds	16,141		—		16,141
U.S. dollar denominated foreign corporate bonds	3,041		—		3,041
Other assets:
Israeli severance funds	2,218		—		2,218
	$	139,071	$	86,166	$	52,905