Cash, Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2017

Cash Cash Equivalents And Short Term Investments [Abstract]

Cash, Cash Equivalents and Marketable Securities

4.	Cash, Cash Equivalents and Marketable Securities

Cash, cash equivalents and marketable securities consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
December 31, 2017
Cash and cash equivalents:
Cash	$	4,041	$	-	$	-		$	4,041
Money market funds		22,543		-		-			22,543
Total cash and cash equivalents		26,584		-		-			26,584
Marketable securities available-for-sale:
U.S. Treasuries		45,559		-		(25	)		45,534
U.S. government agency securities		86,860		-		(40	)		86,820
Corporate debt securities		32,931		-		(15	)		32,916
Total marketable securities available-for-sale		165,350		-		(80	)		165,270
Total cash, cash equivalents and marketable securities	$	191,934	$	-	$	(80	)	$	191,854
December 31, 2016
Cash and cash equivalents:
Cash	$	3,557	$	-	$	-		$	3,557
Money market funds		18,981		-		-			18,981
U.S. government agency securities		1,751		-		-			1,751
Total cash and cash equivalents		24,289		-		-			24,289
Marketable securities available-for-sale:
U.S. Treasuries		3,499		-		-			3,499
U.S. government agency securities		28,685		3		(2	)		28,686
Corporate debt securities		24,938		5		(2	)		24,941
Total marketable securities available-for-sale		57,122		8		(4	)		57,126
Total cash, cash equivalents and marketable securities	$	81,411	$	8	$	(4	)	$	81,415

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

	December 31, 2017
	Amortized Cost		Estimated Fair Value
Mature in one year or less	$	165,350	$	165,270
Mature after one year through two years		-		-
	$	165,350	$	165,270

There were no realized gains or losses from the sale of marketable securities in the years ended December 31, 2017, 2016 and 2015. All of our investments are classified as short-term and available-for-sale, as we consider them available to fund current operations and may not hold our investments until maturity.