INVESTMENTS:

Cash, cash equivalents and short-term investments:

The short-term investments are classified as available-for-sale securities. The cash, cash equivalents and short-term investments at September 30, 2017 and December 31, 2016 were as follows:



	September 30, 2017
	Amortized Cost			Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	53,639		$	—	$	—		$	53,639
Money market funds	4,777			—		—			4,777
Certificates of deposit	77,149			2		(14		)	77,137
U.S. Government and agency securities	45,225			—		(112		)	45,113
Commercial paper	36,992			6		(22		)	36,976
Corporate bonds	94,056			53		(80		)	94,029
Municipal bonds	15,728			—		(31		)	15,697
Foreign government bonds	18,818			1		(28		)	18,791
Total	346,384			62		(287		)	346,159
Less amounts classified as cash and cash equivalents	(58,416		)	—		—			(58,416		)
Short-term investments	$	287,968		$	62	$	(287	)	$	287,743



	December 31, 2016
	Amortized Cost			Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	54,947		$	—	$	—		$	54,947
Money market funds	1,833			—		—			1,833
Certificates of deposit	78,643			—		—			78,643
U.S. Government and agency securities	56,431			2		(86		)	56,347
Commercial paper	29,486			—		(3		)	29,483
Corporate bonds	94,292			37		(167		)	94,162
Municipal bonds	7,718			—		(12		)	7,706
Foreign government bonds	5,327			—		(7		)	5,320
Total	328,677			39		(275		)	328,441
Less amounts classified as cash and cash equivalents	(56,780		)	—		—			(56,780		)
Short-term investments	$	271,897		$	39	$	(275	)	$	271,661

Interest income and gains on short-term investments, net were $1.0 million and $0.7 million for the three months ended September 30, 2017 and 2016, respectively. Interest income and gains on short-term investments, net were $2.8 million and $1.2 million for the nine months ended September 30, 2017 and 2016, respectively. At September 30, 2017, gross unrealized losses on investments that were in a gross unrealized loss position for greater than 12 months were immaterial. These investments were not deemed to be other-than-temporarily impaired and the gross unrealized losses were recorded in other comprehensive income (loss) ("OCI").

The contractual maturities of short-term investments at September 30, 2017 and December 31, 2016 were as follows:



	September 30, 2017				December 31, 2016
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in less than one year	$	204,399	$	204,315	$	157,270	$	157,163
Due in one to three years	83,569		83,428		114,627		114,498
	$	287,968	$	287,743	$	271,897	$	271,661

Equity investments in privately-held companies:

As of September 30, 2017 and December 31, 2016, the Company held a total of $22.2 million and $12.7 million, respectively, in equity investments in privately-held companies.