5)	Investments

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


	Years Ended December 31,
	2014		2013
Available-for-sale investments:
Time deposits and certificates of deposit	$	20,900	$	64,989
Bankers acceptance drafts		82		491
Commercial paper		—		53,434
Corporate obligations		24,020		18,351
Municipal bonds		2,099		—
U.S. agency obligations		82,493		162,450

		129,594		299,715
Trading securities:
Mutual funds (1)		—		1,000

	$	129,594	$	300,715

(1)	The mutual funds are associated with the Company’s supplemental defined contribution retirement obligations.

The fair value of long-term available-for-sale investments with maturities or estimated lives of more than one year consists of the following:


	Years Ended December 31,
	2014		2013
Time deposits and certificates of deposit	$	48	$	54
Asset-backed securities		75,674		—
Corporate obligations		64,669		—
Municipal bonds		1,254		—
U.S. agency obligations		15,556		60,351

	$	157,201	$	60,405

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


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of December 31, 2014:
Short-term investments:
Available-for-sale 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	$	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


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of December 31, 2013:
Short-term investments:
Available-for-sale investments:
Time deposits and certificates of deposit	$	64,983	$	10	$	(4	)	$	64,989
Bankers acceptance drafts		491		—		—			491
Commercial paper		53,429		5		—			53,434
Corporate obligations		18,360		—		(9	)		18,351
U.S. agency obligations		162,430		22		(2	)		162,450

	$	299,693	$	37	$	(15	)	$	299,715

Long-term investments:
Time deposits and certificates of deposit	$	54	$	—	$	—		$	54
U.S. agency obligations		60,374		9		(32	)		60,351

	$	60,428	$	9	$	(32	)	$	60,405

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 and realized gains or losses are reflected in income and was not material in 2014, 2013 and 2012.