Financial Instruments

12 Months Ended

Dec. 31, 2013

Financial Instruments

4. Financial Instruments

Cash equivalents and short-term and long-term investments, all of which are classified as available-for-sale securities, consisted of the following (in thousands):

	December 31, 2013									December 31, 2012
								Estimated									Estimated
			Unrealized		Unrealized			Fair				Unrealized		Unrealized			Fair
	Cost		Gain		(Loss)			Value		Cost		Gain		(Loss)			Value
Money market funds	$	57,296	$	-	$	-		$	57,296	$	43,303	$	-	$	-		$	43,303
Corporate notes and commercial paper		182,426		62		(16	)		182,472		64,403		25		(3	)		64,425
U.S. government agency securities		75,278		23		(12	)		75,289		19,335		11		-			19,346
	$	315,000	$	85	$	(28	)	$	315,057	$	127,041	$	36	$	(3	)	$	127,074
Classified as:
Cash equivalents								$	113,794								$	43,303
Short-term investments									150,892									77,656
Long-term investments									50,371									6,115
Total cash equivalents and investments								$	315,057								$	127,074

At December 31, 2013, the remaining contractual maturities of available-for-sale securities were less than two years. There have been no significant realized gains or losses on available-for-sale securities for the periods presented.