Cash, Cash Equivalents and Marketable Securities

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



March 31, 2016
Description	Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash	$	15,930	$	—	$	—		$	15,930
Cash equivalents:
Commercial paper	2,000		—		—			2,000
Money market mutual funds	1,321		—		—			1,321
Total cash and cash equivalents	19,251		—		—			19,251
Short-term marketable securities:
Commercial paper	7,485		—		—			7,485
Corporate notes and bonds	43,590		7		—			43,597
Government obligations	14,005		6		—			14,011
U.S. agency obligations	28,331		—		—			28,331
Total short-term marketable securities	93,411		13		—			93,424
Marketable securities, noncurrent:
Corporate notes and bonds	2,432		—		(1		)	2,431
Government obligations	2,005		—		—			2,005
U.S. agency obligations	3,100		1		—			3,101
Total marketable securities, noncurrent	7,537		1		(1		)	7,537
Cash, cash equivalents, short-term marketable securities and marketable securities, noncurrent	$	120,199	$	14	$	(1	)	$	120,212



December 31, 2015
Description	Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash	$	9,624	$	—	$	—		$	9,624
Cash equivalents:
Money market mutual funds	246		—		—			246
Total cash and cash equivalents	9,870		—		—			9,870
Short-term marketable securities:
Commercial paper	7,485		—		—			7,485
Corporate notes and bonds	44,483		—		(60		)	44,423
Government obligations	12,010		—		(12		)	11,998
U.S. agency obligations	32,543		—		(39		)	32,504
Total short-term marketable securities	96,521		—		(111		)	96,410
Marketable securities, noncurrent:
Corporate notes and bonds	4,453		—		(17		)	4,436
Government obligations	1,997		—		(4		)	1,993
Total marketable securities, noncurrent	6,450		—		(21		)	6,429
Cash, cash equivalents, short-term marketable securities and marketable securities, noncurrent	$	112,841	$	—	$	(132	)	$	112,709

As of March 31, 2016 and December 31, 2015, we did not consider any of our investments to be other-than-temporarily impaired.

As of March 31, 2016, the following table summarizes the estimated fair value of our investments in marketable securities, all of which are considered available-for-sale, classified by the contractual maturity date (in thousands):



Due within 1 year	$	93,424
Due within 1 year through 3 years	7,537
Total marketable securities	$	100,961