3)	Investments

The fair value of short-term investments with maturities or estimated lives of one year or less consists of the following:


	September 30, 2015		December 31, 2014
Available-for-sale investments:
Time deposits and certificates of deposit	$	21,152	$	20,900
Bankers’ acceptance drafts		266		82
Commercial paper		1,446		—
Corporate obligations		75,433		24,020
Municipal bonds		4,959		2,099
U.S. agency obligations		93,586		82,493

	$	196,842	$	129,594

The fair value of long-term investments with maturities of more than one year consists of the following:


	September 30, 2015		December 31, 2014
Available-for-sale investments:
Time deposits and certificates of deposit	$	—	$	48
Asset-backed securities		134,917		75,674
Corporate obligations		93,990		64,669
Municipal bonds		3,422		1,254
U.S. agency obligations		8,579		15,556

	$	240,908	$	157,201

The following tables show the gross unrealized gains and (losses) aggregated by investment category for short-term and long-term available-for-sale investments:


As of September 30, 2015:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Short-term investments:
Time deposits and certificates of deposit	$	21,152	$	—	$	—		$	21,152
Bankers’ acceptance drafts		266		—		—			266
Commercial paper		1,446		—		—			1,446
Corporate obligations		75,448		9		(24	)		75,433
Municipal bonds		4,953		6		—			4,959
U.S. agency obligations		93,558		36		(8	)		93,586

	$	196,823	$	51	$	(32	)	$	196,842

Long-term investments:
Asset-backed securities	$	134,914	$	71	$	(68	)	$	134,917
Corporate obligations		94,131		39		(180	)		93,990
Municipal bonds		3,400		27		(5	)		3,422
U.S. agency obligations		8,576		3		—			8,579

	$	241,021	$	140	$	(253	)	$	240,908


As of December 31, 2014:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Short-term investments:
Time deposits and certificates of deposit	$	20,901	$	—	$	(1	)	$	20,900
Bankers’ acceptance drafts		82		—		—			82
Corporate obligations		24,029		2		(11	)		24,020
Municipal bonds		2,100		—		(1	)		2,099
U.S. agency obligations		82,488		14		(9	)		82,493

	$	129,600	$	16	$	(22	)	$	129,594

Long-term investments:
Time deposits and certificates of deposit	$	48	$	—	$	—		$	48
Asset-backed securities		75,778		5		(109	)		75,674
Corporate obligations		64,842		1		(174	)		64,669
Municipal bonds		1,258		—		(4	)		1,254
U.S. agency obligations		15,563		2		(9	)		15,556

	$	157,489	$	8	$	(296	)	$	157,201

Interest income is accrued as earned. Dividend income is recognized as income on the date the stock trades “ex-dividend.” The cost of marketable securities sold is determined by the specific identification method. Realized gains or (losses) are reflected in income and were immaterial for both the three and nine months ended September 30, 2015 and 2014.

In accordance with the Company’s investment policy, no security shall have a maturity or average life longer than three years. The average duration of the portfolio shall be no more than one year. Corporate securities must have ratings of A3/A- or better. Asset-backed securities must be rated AAA. Short-term ratings of A-2/P2/F2 or higher are also permitted. With respect to compliance with these investment guidelines, the rating agencies include Moody’s Investor Service, Standard & Poor’s and Fitch Investor Service. The middle of Moody’s, Standard & Poor’s and Fitch rating shall be used to determine compliance with credit quality guidelines. If a security is rated by two rating agencies, the lower rating will apply. If only one rating exists, that rating shall be used.