Available For Sale Marketable Debt Securities (Tables)

3 Months Ended

Mar. 31, 2012

Available For Sale Marketable Debt Securities [Abstract]

Summary Of Amortized Cost And Estimated Fair Value Of Marketable Debt Securities Available For Sale

								Estimated
			Unrealized					Fair
	Cost		Gain		(Loss)			Value
Corporate bonds	$	29,545	$	91	$	(6	)	$	29,630

								Estimated
			Unrealized					Fair
	Cost		Gain		(Loss)			Value
Corporate bonds	$	25,680	$	53	$	(24	)	$	25,709

Summary Of Contractual Maturities Of Available For Sale Debt Securities

	March 31, 2012
			Estimated Fair
	Cost		Value
Less than one year	$	13,660	$	13,679
Due between 1-2 years		8,319		8,363
Due between 2-5 years		7,566		7,588
Total	$	29,545	$	29,630