Cash and Cash Equivalents, Restricted Cash and Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2014

Cash and Cash Equivalents [Abstract]

Schedule of Cash and Cash Equivalents [Table Text Block]

The following table summarizes the Company’s cash and cash equivalents:

	June 30,		December 31,		Recurring Fair
	2014		2013		Value Measurement
	(in thousands)
Cash and cash equivalents:
Cash	$	209,538	$	86,074
Money market funds		88,619		88,769	Level 1
Commercial paper		38,171		11,499	Level 2
Total Cash and cash equivalents	$	336,328	$	186,342

Marketable Securities [Table Text Block]

The following table summarizes the Company’s marketable securities as of June 30, 2014 and December 31, 2013:

	June 30,		December 31,		Recurring Fair
	2014		2013		Value Measurement
	(in thousands)
Marketable securities:
Fixed-income debt securities	$	114,383	$	57,032	Level 2
Commercial paper		49,776		19,615	Level 2
Total Marketable securities	$	164,159	$	76,647

Schedule of Investments Classified By Contractual Maturity Date [Table Text Block]

The following tables present the contractual maturities of the Company’s marketable securities:

	As of June 30, 2014
	Amortized		Unrealized		Estimated
	Cost		Gain		Fair Value
	(in thousands)
Fixed-income debt securities:
Mature after one year and within three years	$	114,300	$	83	$	114,383
Commercial paper:
Mature within one year		49,776		-		49,776
Total	$	164,076	$	83	$	164,159

	As of December 31, 2013
	Amortized		Unrealized		Estimated
	Cost		Loss		Fair Value
	(in thousands)
Fixed-income debt securities:
Mature within one year	$	3,004	$	-	$	3,004
Mature after one year and within three years		54,044		(16)		54,028
Commercial paper:
Mature within one year		19,615		-		19,615
Total	$	76,663	$	(16)	$	76,647