3)	Investments

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


	March 31, 2017		December 31, 2016
Available-for-sale investments:
Time deposits and certificates of deposit	$	3,479	$	23,818
Bankers’ acceptance drafts		1,117		1,439
Asset-backed securities		36,682		36,809
Commercial paper		12,134		24,381
Corporate obligations		51,393		46,707
Municipal bonds		251		591
Promissory note		675		675
U.S. treasury obligations		20,424		25,414
U.S. agency obligations		29,144		29,629

	$	155,299	$	189,463

Investments classified as long-term consists of the following:


	March 31, 2017		December 31, 2016
Available-for-sale investments:
Group insurance contracts	$	5,633	$	5,558
Cost method investments:
Minority interest in a private company⁽¹⁾		4,300		4,300

	$	9,933	$	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:


As of March 31, 2017:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Short-term investments:
Available-for-sale investments:
Time deposits and certificates of deposit	$	3,479	$	—	$	—		$	3,479
Bankers’ acceptance drafts		1,117		—		—			1,117
Asset-backed securities		36,711		12		(41	)		36,682
Commercial paper		12,160		—		(26	)		12,134
Corporate obligations		51,328		70		(5	)		51,393
Municipal bonds		251		—		—			251
Promissory note		675		—		—			675
U.S. treasury obligations		20,418		6		—			20,424
U.S. agency obligations		29,114		34		(4	)		29,144

	$	155,253	$	122	$	(76	)	$	155,299


As of March 31, 2017:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Long-term investments:
Available-for-sale investments:
Group insurance contracts	$	6,497	$	—	$	(864	)	$	5,633


As of December 31, 2016:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
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


As of December 31, 2016:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
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 March 31, 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 three months ended March 31, 2017 and 2016.