Investments

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


	June 30, 2013		December 31, 2012
Available-for-sale investments:
Bankers’ acceptance drafts	$	145	$	242
Time deposits		52,157		52
Commercial paper		46,495		—
U.S. treasury obligations		5,004		13,054
U.S. agency obligations		242,000		313,514

		345,801		326,862

Trading investments:
Mutual funds		914		791

	$	346,715	$	327,653

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


	June 30, 2013		December 31, 2012
Available-for-sale investments:
Time deposits	$	54	$	—
U.S. agency obligations		15,734		12,158

	$	15,788	$	12,158

The following tables show 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 June 30, 2013:
Short-term investments:
Bankers’ acceptance drafts	$	145	$	—	$	—		$	145
Time deposits		52,157		—		—			52,157
Commercial paper		46,495		—		—			46,495
U.S. treasury obligations		5,003		1		—			5,004
U.S. agency obligations		241,992		26		(18	)		242,000

	$	345,792	$	27	$	(18	)	$	345,801

Long-term investments:
Time deposits	$	54	$	—	$	—		$	54
U.S. agency obligations		15,736		1		(3	)		15,734

U.S. agency obligations	$	15,790	$	1	$	(3	)	$	15,788


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of December 31, 2012:
Short-term investments:
Time deposits	$	52	$	—	$	—		$	52
Bankers’ acceptance drafts		242		—		—			242
U.S. treasury obligations		13,045		9		—			13,054
U.S. agency obligations		313,262		258		(6	)		313,514

	$	326,601	$	267	$	(6	)	$	326,862

Long-term investments:
U.S. agency obligations	$	12,156	$	2	$	—		$	12,158

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 not material for the three and six months ended June 30, 2013 and 2012, respectively.

The gains and (losses) for trading investments were immaterial for the three and six months ended June 30, 2013 and 2012.