4. Available-for-Sale Securities and Fair Value Measurements

Available-for Sale Securities

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

(In thousands)	December 31, 2014		December 31, 2013
Cash and cash equivalents	$	95,090	$	125,009
Short-term marketable securities		143,698		321,615
Marketable securities		42,856		55,374
Restricted cash		—		833

Total	$	281,644	$	502,831

The estimated fair value of available-for-sale 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:

	December 31, 2014
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Other Than Temporary Impairment Loss			Estimated Fair Value
U.S. government securities	$	30,019	$	24	$	—		$	—		$	30,043
U.S. government agencies		34,756		6		(12	)		—			34,750
U.S. corporate notes		80,880		5		(110	)		—			80,775
U.S. commercial paper		34,469		—		—			—			34,469
Ordinary shares of Theravance Biopharma		10,269		—		—			(3,752	)		6,517
Money market funds		95,090		—		—			—			95,090

Total	$	285,483	$	35	$	(122	)	$	(3,752	)	$	281,644

	December 31, 2013
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Other Than Temporary Impairment Loss		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

We determined that the unrealized loss on our Theravance Biopharma equity securities as of December 31, 2014 was other-than-temporary. Therefore, we recognized a loss of $3.8 million on these equity securities, which was charged to other income (expense), net on the consolidated statements of operations.

At December 31, 2014, all of the available-for-sale debt securities had contractual maturities within two years and the average duration of debt securities was approximately eight months. We do not intend to sell the investments in debt 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 available-for-sale debt securities at December 31, 2014 were temporary in nature. All available-for-sale debt securities with unrealized losses at December 31, 2014 have been in a loss position for less than twelve months.

During the years ended December 31, 2014, 2013 and 2012, we sold marketable securities totaling $7.2 million, $22.6 million and $49.7 million, and the related realized gains and losses were not significant in any of these periods.

Fair Value Measurements

Our available-for-sale securities are measured at fair value on a recurring basis and our debt is carried at the amortized cost basis. The estimated fair values were as follows:

	Estimated Fair Value Measurements at Reporting Date Using:
	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Types of Instruments (In thousands)	Level 1		Level 2		Level 3		Total
Assets at December 31, 2014
U.S. government securities	$	30,043	$	—	$	—	$	30,043
U.S. government agencies		—		34,750		—		34,750
U.S. corporate notes		—		80,775		—		80,775
U.S. commercial paper		—		34,469		—		34,469
Ordinary shares of Theravance Biopharma		6,517		—		—		6,517
Money market funds		95,090		—		—		95,090

Total assets measured at estimated fair value	$	131,650	$	149,994	$	—	$	281,644


Liabilities at December 31, 2014
Convertible subordinated notes due 2023	$	—	$	197,095	$	—	$	197,095
Non-recourse notes due 2029		—		456,411		—		456,411

Total fair value of liabilities	$	—	$	653,506	$	—	$	653,506

	Estimated Fair Value Measurements at Reporting Date Using:
	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Types of Instruments (In thousands)	Level 1		Level 2		Level 3		Total
Assets at December 31, 2013
U.S. government securities	$	42,158	$	—	$	—	$	42,158
U.S. government agencies		98,236		43,095		—		141,331
U.S. corporate notes		61,591		33,386		—		94,977
U.S. commercial paper		3,499		98,523		—		102,022
Money market funds		122,343		—		—		122,343

Total assets measured at estimated fair value	$	327,827	$	175,004	$	—	$	502,831


Liabilities at December 31, 2013
Convertible subordinated notes due 2023	$	—	$	408,250	$	—	$	408,250

The fair value of our marketable securities classified within Level 2 is based upon observable inputs that may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications.

At December 31, 2014, securities with a total fair value of $8.0 million were measured using Level 2 inputs in comparison to December 31, 2013, at which time such securities had a fair value of $8.0 million and were measured using Level 1 inputs.

The fair value of our convertible subordinated notes due 2023 and non-recourse notes due 2029 is based on actual trading prices of the instruments, if applicable, or pricing models that utilize current observable market characteristics for similar types of instruments.