Available-for-Sale Securities

6 Months Ended

Jun. 30, 2014

Available-for-Sale Securities

Available-for-Sale Securities

4. Available-for-Sale Securities

The classification of available-for-sale securities in the consolidated balance sheets is as follows:

(In thousands)	June 30, 2014		December 31, 2013
Cash and cash equivalents	$	184,994	$	125,009
Short-term investments	126,424		321,615
Marketable securities	34,349		55,374
Restricted cash	833		833
Total	$	346,600	$	502,831

The estimated fair value of available-for-sales securities is based on quoted market prices for these or similar investments that were based on prices obtained from a commercial pricing service. Available-for-sale securities are summarized below:

	June 30, 2014
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government securities	$	23,509	$	44	$	—		$	23,553
U.S. government agencies	54,712		15		(5		)	54,722
U.S. corporate notes	33,632		7		(11		)	33,628
U.S. commercial paper	34,942		—		—			34,942
Equity securities	10,269		3,656		—			13,925
Money market funds	185,830		—		—			185,830
Total	$	342,894	$	3,722	$	(16	)	$	346,600

Equity securities consist of ordinary shares of Theravance Biopharma owned by us as of June 30, 2014.  These equity securities are restricted securities and can only be resold pursuant to a registration statement or an exemption from registration under the Securities Act of 1933, as amended (the “Securities Act”).  We expect to be able to sell these shares pursuant to Rule 144 promulgated under the Securities Act after the satisfaction of a six-month holding period and, therefore, have classified them as available-for-sale marketable securities.

	December 31, 2013
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government securities	$	42,104	$	55	$	(1	)	$	42,158
U.S. government agencies	141,278		61		(8		)	141,331
U.S. corporate notes	94,923		54		—			94,977
U.S. commercial paper	102,021		2		(1		)	102,022
Money market funds	122,343		—		—			122,343
Total	$	502,669	$	172	$	(10	)	$	502,831

At June 30, 2014, all of the available-for-sale debt securities had contractual maturities within two years and the average duration of marketable securities was approximately seven months. We do not intend to sell the investments that are in an unrealized loss position, and it is unlikely that we will be required to sell the investments before recovery of their amortized cost basis, which may be maturity. We have determined that the gross unrealized losses on our marketable securities at June 30, 2104 were temporary in nature. All marketable securities with unrealized losses at June 30, 2014 have been in a loss position for less than twelve months.

During the six months ended June 30, 2014 and 2013, we sold available-for-sale securities totaling $5.0 million and $17.6 million, and the related realized gains and losses were not significant in any of these periods.