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

6 Months Ended

Jun. 30, 2019

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:



	June 30, 2019
	Fair Value		Level 1		Level 2		Level 3

	(unaudited)
	(in thousands)
Financial Assets:
Money market funds	$	24,016	$	24,016	$	—	$	—
U.S. government debt securities	5,007		—		5,007		—
Total cash equivalents	29,023		24,016		5,007		—

Corporate bonds	32,988		—		32,988		—
U.S. government debt securities	332,959		—		332,959		—
U.S. government agency bonds	5,027		—		5,027		—
Total short-term marketable securities	370,974		—		370,974		—

U.S. government debt securities	277,301		—		277,301		—
Total long-term marketable securities	277,301		—		277,301		—
Total	$	677,298	$	24,016	$	653,282	$	—

Financial Liabilities:
Acquisition-related contingent consideration	$	—	$	—	$	1,135	$	—
Total	$	—	$	—	$	1,135	$	—



	December 31, 2018
	Fair Value		Level 1		Level 2		Level 3

	(in thousands)
Financial Assets:
Money market funds	$	25,796	$	25,796	$	—	$	—
Total cash equivalents	25,796		25,796		—		—

Corporate bonds	38,397		—		38,397		—
U.S. government debt securities	235,016		—		235,016		—
U.S. government agency bonds	5,004		—		5,004		—
Total short-term marketable securities	278,417		—		278,417		—

Corporate bonds	3,805		—		3,805		—
U.S. government debt securities	73,758		—		73,758		—
Total long-term marketable securities	77,563		—		77,563		—
Total	$	381,776	$	25,796	$	355,980	$	—

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:



	June 30, 2019
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Estimated Fair Value

	(unaudited)
	(in thousands)
Money market fund	$	24,016	$	—	$	—		$	24,016
Corporate bond	32,919		69		—			32,988
U.S. government debt securities	614,082		1,189		(4		)	615,267
U.S. government agency bonds	5,025		2		—			$	5,027
Total	$	676,042	$	1,260	$	(4	)	$	677,298



	December 31, 2018
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Estimated Fair Value

	(in thousands)
Money market fund	$	25,796	$	—	$	—		$	25,796
Corporate bond	42,273		—		(71		)	42,202
U.S. government debt securities	308,775		235		(236		)	308,774
U.S. government agency bonds	5,014		—		(10		)	5,004
Total	$	381,858	$	235	$	(317	)	$	381,776