Financial Instruments

9 Months Ended

Sep. 30, 2014

Investments Debt And Equity Securities [Abstract]

Financial Instruments

4. Financial Instruments

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

	September 30, 2014									December 31, 2013
								Estimated									Estimated
			Unrealized		Unrealized			Fair				Unrealized		Unrealized			Fair
	Cost		Gain		(Loss)			Value		Cost		Gain		(Loss)			Value
Money market funds	$	13,588	$	—	$	—		$	13,588	$	57,296	$	—	$	—		$	57,296
Corporate notes and commercial paper		164,048		30		(72	)		164,006		182,426		62		(16	)		182,472
U.S. government agency securities		60,978		20		(2	)		60,996		75,278		23		(12	)		75,289
	$	238,614	$	50	$	(74	)	$	238,590	$	315,000	$	85	$	(28	)	$	315,057
Classified as:
Cash equivalents								$	29,727								$	113,794
Short-term investments									172,060									150,892
Long-term investments									36,803									50,371
Total cash equivalents and investments								$	238,590								$	315,057

At September 30, 2014 and 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.