Marketable Securities

12 Months Ended

Dec. 31, 2016

Marketable Securities [Abstract]

Marketable Securities

NOTE 5.      MARKETABLE SECURITIES

During the year ended December 31, 2016, we purchased marketable debt securities, which are classified as available-for-sale and carried at fair value in the accompanying consolidated balance sheets on a trade date basis. We have classified our investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Unrealized holding gains and losses are deferred within accumulated other comprehensive income (“AOCI”), net of applicable taxes, except for when an impairment is determined to be other-than-temporary or the security is divested prior to maturity. Within the accompanying consolidated statements of operations, interest earned and amortization of premiums or discounts on marketable securities are included in interest income, realized gains and losses on the sale of our marketable securities are included in other income.

The amortized cost and fair value of marketable securities were as follows (in thousands):

As of December 31, 2016		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Corporate bonds	$	130,833	$	40	$	(102)	$	130,771
Certificates of deposit		40,400		-		-		40,400
Asset backed securities		27,290		25		-		27,315
Commercial paper		20,228		-		-		20,228
U.S. government bonds		12,244		1		(14)		12,231
Agency bonds		4,600		4		-		4,604
Municipal bonds		1,400		-		-		1,400
Total marketable securities	$	236,995	$	70	$	(116)	$	236,949
As of December 31, 2015		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Corporate bonds	$	177,810	$	24	$	(221)	$	177,613
U.S. government bonds		12,881		-		(10)		12,871
Agency bonds		12,068		-		(3)		12,065
Certificates of deposit		3,500		-		-		3,500
Commercial paper		3,491		-		-		3,491
International government bonds		1,462		-		(3)		1,459
Municipal bonds		1,400		-		(1)		1,399
Treasury bill		1,192		1		-		1,193
Total marketable securities	$	213,804	$	25	$	(238)	$	213,591

No marketable securities have been in a continuous unrealized loss position for more than twelve months. Our portfolio of marketable securities had an average AA- credit rating as of December 31, 2016. There were no marketable securities that we consider to be other-than-temporarily impaired as of December 31, 2016. Our investment strategy is to buy short-duration marketable securities with a high credit rating. Some of our marketable securities have call features that can effectively shorten the lifespan from the contractual maturity date. We use effective maturity date to measure the duration of the marketable securities.

Remaining effective maturities of marketable securities were as follows (in thousands):

As of December 31, 2016		Amortized Cost		Fair Value
Due in one year or less	$	169,044	$	169,002
Due after one through two years		67,951		67,947
	$	236,995	$	236,949