Short-term Investments

6 Months Ended

Jun. 30, 2013

Short-term Investment [Abstract]

Short-term Investments [Text Block]

Short-term Investments

The following table summarizes the Company’s investments in available-for-sale securities as of June 30, 2013 and December 31, 2012 (in thousands):

	June 30, 2013
			Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Municipal bonds	$	150,450	$	40	$	(1	)	$	150,489
U.S. government and agency securities	5,499		—		—			5,499
Corporate bonds	4,040		—		(1		)	4,039
	$	159,989	$	40	$	(2	)	$	160,027

	December 31, 2012
			Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Commercial paper	$	13,697	$	—	$	—		$	13,697
Municipal bonds	105,536		1		(22		)	105,515
Corporate bonds	6,880		—		—			6,880
	$	126,113	$	1	$	(22	)	$	126,092

Available-for-sale securities are reported at fair value, with unrealized gains and losses, net of tax, included as a separate component of stockholders’ equity within accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in other income (expense), net in the Company’s condensed consolidated statements of operations.

The weighted-average remaining maturity of the Company’s investment portfolio was less than one year as of June 30, 2013 and December 31, 2012. As of June 30, 2013, no individual securities incurred continuous unrealized losses for greater than 12 months.