3)	Investments

The fair value of investments classified as short-term consists of the following:


	June 30, 2017		December 31, 2016
Available-for-sale investments:
Time deposits and certificates of deposit	$	13,530	$	23,818
Bankers’ acceptance drafts		1,934		1,439
Asset-backed securities		32,632		36,809
Commercial paper		11,629		24,381
Corporate obligations		46,990		46,707
Municipal bonds		250		591
Promissory note		675		675
U.S. treasury obligations		16,928		25,414
U.S. agency obligations		24,448		29,629

	$	149,016	$	189,463

Investments classified as long-term consists of the following:


	June 30, 2017		December 31, 2016
Available-for-sale investments:
Group insurance contracts	$	6,029	$	5,558
Cost method investments:
Minority interest in a private company⁽¹⁾		4,300		4,300

	$	10,329	$	9,858

⁽¹⁾	In April 2016, the Company invested $9,300 for a minority interest in a private company. For the year ended December 31, 2016, the Company recognized $5,000 of impairment charges related to this cost method investment.

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


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of June 30, 2017:
Short-term investments:
Available-for-sale investments:
Time deposits and certificates of deposit	$	13,530	$	—	$	—		$	13,530
Bankers’ acceptance drafts		1,934		—		—			1,934
Asset-backed securities		32,655		13		(36	)		32,632
Commercial paper		11,664		—		(35	)		11,629
Corporate obligations		46,915		81		(6	)		46,990
Municipal bonds		250		—		—			250
Promissory note		675		—		—			675
U.S. treasury obligations		16,905		23		—			16,928
U.S. agency obligations		24,437		14		(3	)		24,448

	$	148,965	$	131	$	(80	)	$	149,016


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of June 30, 2017:
Long-term investments:
Available-for-sale investments:
Group insurance contracts	$	6,888	$	—	$	(859	)	$	6,029


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of December 31, 2016:
Short-term investments:
Available-for-sale investments:
Time deposits and certificates of deposit	$	23,818	$	—	$	—		$	23,818
Bankers acceptance drafts		1,439		—		—			1,439
Asset-backed securities		36,847		6		(44	)		36,809
Commercial paper		24,423		—		(42	)		24,381
Corporate obligations		46,700		21		(14	)		46,707
Municipal bonds		591		—		—			591
Promissory note		675		—		—			675
U.S. treasury obligations		25,414		—		—			25,414
U.S. agency obligations		29,631		8		(10	)		29,629

	$	189,538	$	35	$	(110	)	$	189,463


	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
As of December 31, 2016:
Long-term investments:
Available-for-sale investments:
Group insurance contracts	$	6,276	$	—	$	(718	)	$	5,558

The tables above, which show the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments as of June 30, 2017 and December 31, 2016, reflect the inclusion within short-term investments of investments with contractual maturities greater than one year from the date of purchase. Management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term on the accompanying balance sheets.

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 six months ended June 30, 2017 and 2016.