Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2013

Investments All Other Investments [Abstract]

Schedule of Cash, Cash Equivalents and Marketable Securities

The following tables show our cash and available-for-sale securities’ amortized cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category recorded as cash and cash equivalents or short and long-term marketable securities as of June 30, 2013 and December 31, 2012 (in thousands):

	June 30, 2013
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
Cash	$	154,775	$	—	$	—		$	154,775	$	154,775	$	—	$	—
Level 1:
Money market funds		10,963		—		—			10,963		10,963		—		—
Subtotal		10,963		—		—			10,963		10,963		—		—
Level 2:
U.S. agency securities		79,048		11		(126	)		78,933		—		29,375		49,558
U.S. treasury securities		49,616		—		(1	)		49,615		34,320		15,295		—
Certificates of deposit		23,701		28		—			23,729		—		21,127		2,602
Commercial paper		15,492		4		—			15,496		—		15,496		—
Corporate securities		278,457		16		(1,023	)		277,450		—		109,745		167,705
Municipal securities		5,001		—		(2	)		4,999		—		4,999		—
Subtotal		451,315		59		(1,152	)		450,222		34,320		196,037		219,865
Total	$	617,053	$	59	$	(1,152	)	$	615,960	$	200,058	$	196,037	$	219,865

	December 31, 2012
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
Cash	$	141,460	$	—	$	—		$	141,460	$	141,460	$	—	$	—
Level 1:
Money market funds		215,052		—		—			215,052		215,052		—		—
Subtotal		215,052		—		—			215,052		215,052		—		—
Level 2:
U.S. agency securities		13,634		4		(3	)		13,635		—		7,635		6,000
Commercial paper		48,710		15		(22	)		48,703		9,999		38,704		—
Corporate securities		162,050		12		(180	)		161,882		1,004		67,630		93,248
Municipal securities		5,003		—		(2	)		5,001		—		5,001		—
Subtotal		229,397		31		(207	)		229,221		11,003		118,970		99,248
Total	$	585,909	$	31	$	(207	)	$	585,733	$	367,515	$	118,970	$	99,248

Fair Value and Notional Principal Amounts of Outstanding or Unsettled Derivative Instruments

The following tables show the fair value and notional principal amounts of our outstanding or unsettled derivative instruments that are not designated as hedging instruments (in thousands):

	Balance Sheet Caption	June 30, 2013
		Fair Value of Derivative (2)				U.S. Dollar Notional
		Asset		Liability
Foreign exchange-forward contracts (current)	Accrued and other current liabilities (1)	$	—	$	1	$	23,042

	Balance Sheet Caption	December 31, 2012
		Fair Value of Derivative (2)				U.S. Dollar Notional
		Asset		Liability
Foreign exchange-forward contracts (current)	Accrued and other current liabilities (1)	$	—	$	64	$	2,710

(1) Derivative contracts address foreign exchange fluctuations for the Euro versus the U.S. dollar.

(2) The fair value of our derivatives are measured using Level 2 fair value inputs, as we use a pricing model that takes into account the contract terms as well as current foreign currency exchange rates in active markets.