Available-for-Sale-Securities (Tables)

6 Months Ended

Jun. 30, 2015

Available-for-sale Securities [Abstract]

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

The following table is a summary of available-for-sale securities recorded in cash and cash equivalents or marketable securities in our Consolidated Balance Sheets (in thousands):

	June 30, 2015									December 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Certificate of deposits	$	—	$	—	$	—		$	—	$	249.0	$	—	$	—	$	249.0
Corporate debt securities	1,065.0		—		(1.8		)	1,063.2		—		—		—		—
Money market funds	11,635.0		—		—			11,635.0		12,791.9		—		—		12,791.9
Municipal debt securities	15,620.5		3.7		—			15,624.2		9,317.3		1.3		—		9,318.6
Total	$	28,320.5	$	3.7	$	(1.8	)	$	28,322.4	$	22,358.2	$	1.3	$	—	$	22,359.5

Marketable Securities [Table Text Block]

Estimated fair values of available-for-sale securities are generally based on prices obtained from commercial pricing services. The following table summarizes the classification of the available-for-sale debt securities on our Consolidated Balance Sheets (in thousands):

	June 30, 2015		December 31, 2014
Cash and cash equivalents	$	25,310.7	$	15,279.4
Marketable securities	3,011.7		7,080.1
Total	$	28,322.4	$	22,359.5

Investments Classified by Contractual Maturity Date [Table Text Block]

The following table summarizes our portfolio of available-for-sale debt securities by contractual maturity (in thousands):

	June 30, 2015
	Amortized Cost		Estimated Fair Value
Less than one year	$	28,320.5	$	28,322.4
Greater than one year	—		—
Total	$	28,320.5	$	28,322.4