Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

nvestments in available-for-sale securities at December 31 were classified as follows:

	2014		2013
Current	$	—	$	239,388
Non-current	15,414		—
Total available-for-sale securities	$	15,414	$	239,388

Available-for-sale Securities

The cost, gross unrealized gains, gross unrealized losses and fair value of the Company's available-for-sale securities were as follows:

	December 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Equity securities	$	15,050	$	364	$	—	$	15,414
Total available-for-sale securities	$	15,050	$	364	$	—	$	15,414

	December 31, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
Debt securities
Corporate bonds	$	108,300	$	340	$	(69	)	$	108,571
U.S. government debt (2)	106,335		60		(79		)	106,316
Asset-backed securities	24,478		34		(11		)	24,501
Total available-for-sale securities	$	239,113	$	434	$	(159	)	$	239,388

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(1) All unrealized loss positions were held at a loss for less than 12 months.

(2) U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.

Schedule of Realized Gain (Loss)

	Year Ended December 31,
	2014			2013
Proceeds from sales and maturities of securities	$	342,045		$	7,770
Gross realized gains	1,311			$	20
Gross realized losses	(99		)	$	(39	)