Investments (Tables)

6 Months Ended

Jun. 30, 2017

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