Investments (Tables)

3 Months Ended

Mar. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Fair Value of Short-Term Available-for-Sale Investments

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


	March 31, 2015		December 31, 2014
Available-for-sale investments:
Time deposits and certificates of deposit	$	5,400	$	20,900
Bankers’ acceptance drafts		327		82
Commercial paper		1,447		—
Corporate obligations		58,331		24,020
Municipal bonds		5,798		2,099
U.S. agency obligations		87,328		82,493

	$	158,631	$	129,594

Fair Value of Long-Term Available-for-Sale Investments

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


	March 31, 2015		December 31, 2014
Available-for-sale investments:
Time deposits and certificates of deposit	$	—	$	48
Asset-backed securities		129,242		75,674
Corporate obligations		90,114		64,669
Municipal bonds		1,880		1,254
U.S. agency obligations		16,077		15,556

	$	237,313	$	157,201

Gross Unrealized Gains and (Losses) Aggregated by Investment Category Short-Term and Long-Term Securities

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


As of March 31, 2015:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Short-term investments:
Time deposits and certificates of deposit	$	5,400	$	—	$	—		$	5,400
Bankers’ acceptance drafts		327		—		—			327
Commercial paper		1,447		—		—			1,447
Corporate obligations		58,336		10		(15	)		58,331
Municipal bonds		5,800		1		(3	)		5,798
U.S. agency obligations		87,311		23		(6	)		87,328

	$	158,621	$	34	$	(24	)	$	158,631

Long-term investments:
Asset-backed securities		129,209	$	66	$	(33	)	$	129,242
Corporate obligations		90,128		44		(58	)		90,114
Municipal bonds		1,878		3		(1	)		1,880
U.S. agency obligations		16,070		8		(1	)		16,077

	$	237,285	$	121	$	(93	)	$	237,313


As of December 31, 2014:	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Estimated Fair Value
Short-term investments:
Time deposits and certificates of deposit	$	20,901	$	—	$	(1	)	$	20,900
Bankers’ acceptance drafts		82		—		—			82
Corporate obligations		24,029		2		(11	)		24,020
Municipal bonds		2,100		—		(1	)		2,099
U.S. agency obligations		82,488		14		(9	)		82,493

	$	129,600	$	16	$	(22	)	$	129,594

Long-term investments:
Time deposits and certificates of deposit	$	48	$	—	$	—		$	48
Asset-backed securities		75,778		5		(109	)		75,674
Corporate obligations		64,842		1		(174	)		64,669
Municipal bonds		1,258		—		(4	)		1,254
U.S. agency obligations		15,563		2		(9	)		15,556

	$	157,489	$	8	$	(296	)	$	157,201