Cash Equivalents and Marketable Debt Securities (Tables)

3 Months Ended

Mar. 31, 2018

Cash Equivalents And Marketable Securities [Abstract]

Schedule of Cash Equivalents and Marketable Debt Securities Available-for-Sale

As of March 31, 2018, all of the Company’s marketable debt securities are classified as available-for-sale and are scheduled to mature within 3.5 years. At March 31, 2018, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands):

	March 31, 2018
	(unaudited)
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Corporate debt securities	$	86,952	$	1	$	(222	)	$	86,731
Government sponsored securities		12,508		—		(15	)		12,493
Foreign government bonds		5,936		—		(5	)		5,931
Commercial paper		5,441		—		(3	)		5,438
Current portion		110,837		1		(245	)		110,593
Noncurrent:
Corporate debt securities		12,642		—		(248	)		12,394
Government sponsored securities		2,759		—		(62	)		2,697
Noncurrent portion		15,401		-		(310	)		15,091
Total	$	126,238	$	1	$	(555	)	$	125,684

At December 31, 2017, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands):

	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Corporate debt securities	$	82,188	$	5	$	(84	)	$	82,109
Government sponsored securities		19,261		—		(28	)		19,233
Foreign government bonds		6,441		—		(5	)		6,436
Current portion		107,890		5		(117	)		107,778
Noncurrent:
Corporate debt securities		27,109		—		(226	)		26,883
Government sponsored securities		2,760		—		(43	)		2,717
Noncurrent portion		29,869		—		(269	)		29,600
Total	$	137,759	$	5	$	(386	)	$	137,378

Available-for-Sale Investments in Unrealized Loss Position

Available-for-sale investments that had been in an unrealized loss position for more and less than 12 months at March 31, 2018 and December 31, 2017 are as follows (in thousands):

	March 31, 2018
	(unaudited)
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Corporate debt securities	$	73,914	$	(208	)	$	23,211	$	(262	)
Government sponsored securities		1,999		(7	)		13,191		(70	)
Foreign government bonds		4,533		(2	)		1,397		(3	)
Commercial paper		5,438		(3	)		—		—
Total	$	85,884	$	(220	)	$	37,799	$	(335	)

	December 31, 2017
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Corporate debt securities	$	67,522	$	(104	)	$	35,918	$	(206	)
Government sponsored securities		9,744		(20	)		12,205		(51	)
Foreign government bonds		1,542		—			1,396		(5	)
Total	$	78,808	$	(124	)	$	49,519	$	(262	)

Schedule of Realized Gains and Losses on Sales or Maturities of Available-for-Sale Securities

The Company recorded realized gains and losses on sales or maturities of available-for-sale securities as follows (in thousands):

	Three Months Ended March 31,
	(unaudited)
	2018		2017
Gross realized gains	$	2	$	2
Gross realized losses		—		(5	)
Net realized gains	$	2	$	(3	)