Investments (Tables)

3 Months Ended

Mar. 31, 2017

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