Fair Value Measurements. Cash Equivalents and Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Measurements, Recurring and Nonrecurring

The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows:



	September 30, 2018
	Fair Value		Level 1		Level 2		Level 3

	(unaudited)
	(in thousands)
Financial Assets:
Money market funds	$	360	$	360	$	—	$	—
Total cash equivalents	360		360		—		—

Corporate bonds	48,365		—		48,365		—
U.S. government debt securities	104,044		—		104,044		—
U.S. government agency bonds	4,976		—		4,976		—
Total short-term marketable securities	157,385		—		157,385		—

U.S. government debt securities	2,963		—		2,963		—
Total long-term marketable securities	2,963		—		2,963		—
Total	$	160,708	$	360	$	160,348	$	—



	December 31, 2017
	Fair Value		Level 1		Level 2		Level 3

	(in thousands)
Financial Assets:
Money market funds	$	33,485	$	33,485	$	—	$	—
Total cash equivalents	33,485		33,485		—		—

Corporate bonds	48,075		—		48,075		—
U.S. government debt securities	100,965		—		100,965		—
Total short-term marketable securities	149,040		—		149,040		—

Corporate bonds	6,698		—		6,698		—
U.S. government debt securities	66,556		—		66,556		—
Total long-term marketable securities	73,254		—		73,254		—
Total	$	255,779	$	33,485	$	222,294	$	—

Debt Securities, Available-for-sale

The following tables summarizes the Company’s cash equivalents and marketable securities’ amortized costs, gross unrealized gains, gross unrealized losses and estimated fair values by significant investment category:



	September 30, 2018
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Estimated Fair Value

	(unaudited)
	(in thousands)
Money market fund	$	360	$	—	$	—		$	360
Corporate bond	48,434		1		(70		)	48,365
U.S. government debt securities	107,434		—		(427		)	107,007
U.S. government agency bonds	$	4,984	$	—	$	(8	)	$	4,976
Total	$	161,212	$	1	$	(505	)	$	160,708



	December 31, 2017
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Estimated Fair Value

	(in thousands)
Money market fund	$	33,485	$	—	$	—		$	33,485
Corporate bond	54,879		—		(106		)	54,773
U.S. government debt securities	167,947		—		(426		)	167,521
Total	$	256,311	$	—	$	(532	)	$	255,779