Investments (Tables)

3 Months Ended

Mar. 31, 2019

Investments Debt And Equity Securities [Abstract]

Schedule of Investments

Investments consisted of the following (in thousands):

			Gross Unrealized
					Losses
	Amortized				Less than			Greater than			Estimated
March 31, 2019	Cost		Gains		One Year			One Year			Fair Value
Short-term investments:
Available-for-sale securities:
Corporate debt securities	$	156,443	$	349	$	(11	)	$	(149	)	$	156,632
U.S. government and agency debt securities		108,113		257		(4	)		(45	)		108,321
International government agency debt securities		91,818		193		—			(70	)		91,941
Total short-term investments		356,374		799		(15	)		(264	)		356,894
Long-term investments:
Available-for-sale securities:
Corporate debt securities		28,570		—		(84	)		(45	)		28,441
U.S. government and agency debt securities		10,984		—		(4	)		(5	)		10,975
		39,554		—		(88	)		(50	)	$	39,416
Held-to-maturity securities:
Certificates of deposit		1,820		—		—			—			1,820
Fixed term deposit account		1,667		102		—			—			1,769
		3,487		102		—			—			3,589
Total long-term investments		43,041		102		(88	)		(50	)		43,005
Total investments		399,415		901		(103	)		(314	)		399,899
December 31, 2018
Short-term investments:
Available-for-sale securities:
Corporate debt securities	$	120,197	$	57	$	(62	)	$	(274	)	$	119,918
U.S. government and agency debt securities		80,055		115		(11	)		(87	)		80,072
International government agency debt securities		72,091		85		(8	)		(117	)		72,051
		272,343		257		(81	)		(478	)		272,041
Held-to-maturity securities:
Corporate debt securities		492		—		—			—			492
Total short-term investments		272,835		257		(81	)		(478	)		272,533
Long-term investments:
Available-for-sale securities:
Corporate debt securities		53,505		—		(185	)		(93	)	$	53,227
U.S. government and agency debt securities		18,474		—		(21	)		(12	)		18,441
International government agency debt securities		5,457		—		(4	)		—			5,453
		77,436		—		(210	)		(105	)		77,121
Held-to-maturity securities:
Certificates of deposit		1,820		—		—			—			1,820
Fixed term deposit account		1,667		136		—			—			1,803
		3,487		136		—			—			3,623
Total long-term investments		80,923		136		(210	)		(105	)		80,744
Total investments	$	353,758	$	393	$	(291	)	$	(583	)	$	353,277

Schedule of Proceeds From Sales and Maturities of Marketable Securities Plus the Resulting Realized Gains and Losses

The proceeds from the sales and maturities of marketable securities, which were identified using the specific identification method and were primarily reinvested, were as follows:

	Three Months Ended March 31,
(In thousands)	2019		2018
Proceeds from the sales and maturities of marketable securities	$	55,978	$	79,500
Realized gains	$	—	$	1
Realized losses	$	492	$	4

Schedule of Contractual Maturities of Available-for-Sale and Held-to-Maturity Securities

The Company’s available-for-sale and held-to-maturity securities at March 31, 2019 had contractual maturities in the following periods:

	Available-for-sale				Held-to-maturity
	Amortized		Estimated		Amortized		Estimated
(In thousands)	Cost		Fair Value		Cost		Fair Value
Within 1 year	$	213,318	$	213,172	$	1,820	$	1,820
After 1 year through 5 years		182,610		183,138		1,667		1,769
Total	$	395,928	$	396,310	$	3,487	$	3,589