Marketable Securities and Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2017

Notes To Financial Statements [Abstract]

Short-Term And Long-Term Marketable Securities

As of June 30, 2017 and December 31, 2016, the estimated fair value of our short-term and long-term marketable securities, classified as available for sale, are as follows (in thousands):

Short-term

June 30, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	32,965	$	—	$	—		$	32,965
Corporate bonds	146,853		21		(97		)	146,777
Municipal securities	3,286		—		—			3,286
U.S. government agency bonds	6,763		—		(7		)	6,756
U.S. government treasury bonds	48,261		—		(50		)	48,211
Certificates of deposit	5,791		—		—			5,791
Total marketable securities, short-term	$	243,919	$	21	$	(154	)	$	243,786

Long-term

June 30, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. government agency bonds	$	10,026	$	13	$	(6	)	$	10,033
Corporate bonds	57,558		49		(20		)	57,587
U.S. government treasury bonds	7,019		—		(20		)	6,999
Total marketable securities, long-term	$	74,603	$	62	$	(46	)	$	74,619

Short-term

December 31, 2016	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	42,397	$	—	$	(6	)	$	42,391
Corporate bonds	122,788		22		(121		)	122,689
Municipal securities	5,852		—		(5		)	5,847
U.S. government agency bonds	28,903		9		(4		)	28,908
U.S. government treasury bonds	45,146		7		(7		)	45,146
Certificates of deposit	6,000		—		—			6,000
Total marketable securities, short-term	$	251,086	$	38	$	(143	)	$	250,981

Long-term

December 31, 2016	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. government agency bonds	$	6,805	$	—	$	(16	)	$	6,789
Corporate bonds	40,889		8		(85		)	40,812
U.S. government treasury bonds	12,016		5		(16		)	12,005
Asset-backed securities	177		—		—			177
Total marketable securities, long-term	$	59,887	$	13	$	(117	)	$	59,783

Investments Classified by Contractual Maturity Date

As the carrying value approximates the fair value for our short-term and long-term marketable securities shown in the tables above, the following table summarizes the fair value of our short-term and long-term marketable securities classified by maturity as of June 30, 2017 and December 31, 2016 (in thousands):

	June 30, 2017		December 31, 2016
One year or less	$	243,786	$	250,981
Due in greater than one year	74,619		59,783
Total available for sale short-term and long-term marketable securities	$	318,405	$	310,764

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The following table summarizes the reconciliation of assets measured and recorded at fair value on a recurring basis using significant unobservable inputs Level 3 (in thousands):

	Long-term Notes Receivable
Balance as of December 31, 2016	$	2,047
Additional note receivable issued	2,000
Accrued interest receivable	28
Change in fair value recognized in earnings (losses)	(12		)
Balance as of June 30, 2017	$	4,063

Financial Assets Measured At Fair Value On Recurring Basis

The following tables summarize our financial assets measured at fair value on a recurring basis as of June 30, 2017 and December 31, 2016 (in thousands):

Description	Balance as of June 30, 2017		Quoted Prices in Active  Markets for Identical Assets (Level 1)		Significant Other Observable  Inputs (Level 2)		Significant Other Observable  Inputs (Level 3)
Cash equivalents:
Money market funds	$	199,302	$	199,302	$	—	$	—
Commercial paper	26,282		—		26,282		—
Corporate bonds	3,381		—		3,381		—
U.S. government treasury bonds	2,995		2,995		—		—
U.S. government agency bonds	4,989		—		4,989		—
Short-term investments:
Commercial paper	32,965		—		32,965		—
Corporate bonds	146,777		—		146,777		—
Municipal securities	3,286		—		3,286		—
U.S. government agency bonds	6,756		—		6,756		—
U.S. government treasury bonds	48,211		48,211		—		—
Certificates of deposit	5,791		—		5,791		—
Long-term investments:
U.S. government agency bonds	10,033		—		10,033		—
Corporate bonds	57,587		—		57,587		—
U.S. government treasury bonds	6,999		6,999		—		—
Prepaid expenses and other current assets:
Israeli funds	3,411		—		3,411		—
Other assets:
Long-term notes receivable	4,063		—		—		4,063
	$	562,828	$	257,507	$	301,258	$	4,063

Description	Balance as of December 31, 2016		Quoted Prices in Active  Markets for Identical Assets (Level 1)		Significant Other Observable  Inputs (Level 2)		Significant Other Observable  Inputs (Level 3)
Cash equivalents:
Money market funds	$	87,179	$	87,179	$	—	$	—
Commercial paper	2,499		—		2,499		—
Corporate bonds	750		—		750		—
Short-term investments:
Commercial paper	42,391		—		42,391		—
Corporate bonds	122,689		—		122,689		—
Municipal securities	5,847		—		5,847		—
U.S. government agency bonds	28,908		—		28,908		—
U.S. government treasury bonds	45,146		45,146		—		—
Certificates of deposit	6,000		—		6,000		—
Long-term investments:
U.S. government agency bonds	6,789		—		6,789		—
Corporate bonds	40,812		—		40,812		—
U.S. government treasury bonds	12,005		12,005		—		—
Asset-backed securities	177		—		177		—
Prepaid expenses and other current assets:
Israeli funds	2,956		—		2,956		—
Other assets:
Long-term notes receivable	2,047		—		—		2,047
	$	406,195	$	144,330	$	259,818	$	2,047