Investments

6 Months Ended

Jun. 30, 2020

Investments Debt And Equity Securities [Abstract]

Investments

4. INVESTMENTS

Investments consisted of the following (in thousands):

			Gross Unrealized
					Losses
	Amortized				Less than			Greater than			Estimated
June 30, 2020	Cost		Gains		One Year			One Year			Fair Value
Short-term investments:
Available-for-sale securities:
Corporate debt securities	$	163,761	$	1,774	$	(13	)	$	(3	)	$	165,519
U.S. government and agency debt securities		98,689		827		(2	)		—			99,514
International government agency debt securities		77,624		919		(15	)		—			78,528
Total short-term investments		340,074		3,520		(30	)		(3	)		343,561
Long-term investments:
Available-for-sale securities:
Corporate debt securities		3,452		—		(3	)		—			3,449
		3,452		—		(3	)		—			3,449
Held-to-maturity securities:
Certificates of deposit		1,820		—		—			—			1,820
Fixed term deposit account		1,668		96		—			—			1,764
		3,488		96		—			—			3,584
Total long-term investments		6,940		96		(3	)		—			7,033
Total investments	$	347,014	$	3,616	$	(33	)	$	(3	)	$	350,594
December 31, 2019
Short-term investments:
Available-for-sale securities:
Corporate debt securities	$	144,161	$	676	$	—		$	—		$	144,837
U.S. government and agency debt securities		112,948		434		(1	)		(1	)		113,380
International government agency debt securities		72,753		248		(10	)		—			72,991
Total short-term investments		329,862		1,358		(11	)		(1	)		331,208
Long-term investments:
Available-for-sale securities:
Corporate debt securities		51,070		—		(45	)		(7	)		51,018
International government agency debt securities		20,806		—		(18	)		—			20,788
U.S. government and agency debt securities		4,000		—		(4	)		—			3,996
		75,876		—		(67	)		(7	)		75,802
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		79,363		102		(67	)		(7	)		79,391
Total investments	$	409,225	$	1,460	$	(78	)	$	(8	)	$	410,599

At June 30, 2020, the Company believed that the unrealized losses on its available-for-sale investments were temporary and were not due to credit losses. The investments with unrealized losses consisted primarily of corporate debt securities. In making the determination that the decline in fair value of these securities was temporary, the Company considered various factors, including, but not limited to: the length of time each security was in an unrealized loss position; the extent to which fair value was less than cost; financial condition and near-term prospects of the issuers of the securities; the Company’s intent not to sell these securities; and the assessment that it is more likely than not that the Company would not be required to sell these securities before the recovery of their amortized cost basis.

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:

	Six Months Ended June 30,
(In thousands)	2020		2019
Proceeds from the sales and maturities of marketable securities	$	147,859	$	79,104
Realized gains	$	51	$	—
Realized losses	$	—	$	5

The Company’s available-for-sale and held-to-maturity securities at June 30, 2020 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	$	239,195	$	240,864	$	1,820	$	1,820
After 1 year through 5 years		104,331		106,146		1,668		1,764
Total	$	343,526	$	347,010	$	3,488	$	3,584