3. Cash, cash equivalents and marketable securities

The following is a summary of cash, cash equivalents and marketable securities available-for-sale as of March 31, 2016 and December 31, 2015 (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
March 31, 2016
Cash and cash equivalents:
Cash	$	6,030	$	-	$	-		$	6,030
Money market funds		24,982		-		-			24,982
U.S. Government agency securities		4,999		-		-			4,999
Corporate debt securities		2,847		-		-			2,847
Total cash and cash equivalents		38,858		-		-			38,858
Marketable securities available-for-sale:
U.S. Treasuries		6,573		2		(1	)		6,574
U.S. Government agency securities		24,604		8	-				24,612
Corporate debt securities		96,691		112	-				96,803
Total marketable securities available-for-sale		127,868		122		(1	)		127,989
Total cash, cash equivalents and marketable securities	$	166,726	$	122	$	(1	)	$	166,847
December 31, 2015
Cash and cash equivalents:
Cash	$	4,561	$	-	$	-		$	4,561
Money market funds		21,193		-		-			21,193
Corporate debt securities		19,052		7		(1	)		19,058
Total cash and cash equivalents		44,806		7		(1	)		44,812
Marketable securities available-for-sale:
U.S. Government agency securities		17,628		-		(6	)		17,622
Corporate debt securities		133,679		71		(59	)		133,691
Total marketable securities available-for-sale		151,307		71		(65	)		151,313
Total cash, cash equivalents and marketable securities	$	196,113	$	78	$	(66	)	$	196,125

The maturities of our marketable securities available-for-sale are as follows (in thousands):

	March 31, 2016
	Amortized Cost		Estimated Fair Value
Mature in one year or less	$	127,868	$	127,989
Mature after one year through two years		-		-
	$	127,868	$	127,989

We have classified our entire investment portfolio as available-for-sale and available for use in current operations and accordingly have classified all investments as short-term. Available-for-sale securities are carried at fair value, with unrealized gains and losses included in accumulated other comprehensive income (loss) in stockholders’ equity. Realized gains and losses and declines in value, if any, judged to be other than temporary on available-for-sale securities are included in interest income or expense. The cost of securities sold is based on the specific identification method. Management assesses whether declines in the fair value of investment securities are other than temporary. In determining whether a decline is other than temporary, management considers the following factors:

Whether the investment has been in a continuous realized loss position for over 12 months;

the duration to maturity of our investments;

our intention and ability to hold the investments to maturity and if it is not more likely than not that we will be required to sell the investment before recovery of the amortized cost bases;

the credit rating, financial condition and near-term prospects of the issuer; and

the type of investments made.

To date, there have been no declines in fair value that have been identified as other than temporary.