3. Investments

Available-for-sale investments as of March 31, 2016 and December 31, 2015 were as follows (in thousands):

	March 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	9,307	$	4	$	-		$	9,311
Government-sponsored enterprises		28,662		10		-			28,672
Corporate debt securities		114,475		47		(9	)		114,513
Total	$	152,444	$	61	$	(9	)	$	152,496

	December 31, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	9,354	$	1	$	(6	)	$	9,349
Government-sponsored enterprises		22,055		1		(9	)		22,047
Corporate debt securities		111,473		42		(34	)		111,481
Total	$	142,882	$	44	$	(49	)	$	142,877

All of the Company's available-for-sale investments held at March 31, 2016 and December 31, 2015 had maturity dates of less than one year, and all available-for-sale investments in an unrealized loss position as of March 31, 2016 and December 31, 2015 were in a loss position for less than twelve months. There were no unrealized losses at March 31, 2016 or December 31, 2015 that the Company determined to be other-than-temporary.