Note 4. Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	June 30, 2012
	Fair Value		Level 1		Level 2
Cash equivalents
Money market funds	$	1,068	$	1,068	$	-
Commercial paper		18,499		-		18,499
Municipal bonds		2,049		-		2,049
	$	21,616	$	1,068	$	20,548
Short-term investments
Commercial paper	$	4,496	$	-	$	4,496
Municipal bonds		122,174		-		122,174
Corporate bonds		8,148		-		8,148
U.S. government and agency securities		16,999		-		16,999
	$	151,817	$	-	$	151,817

	December 31, 2011
	Fair Value		Level 1		Level 2
Cash equivalents
Money market funds	$	21,504	$	21,504	$	-
Commercial paper		24,405		-		24,405
Municipal bonds		8,385		-		8,385
Corporate bonds		2,045		-		2,045
	$	56,339	$	21,504	$	34,835

Short-term investments
Commercial paper	$	4,850	$	-	$	4,850
Municipal bonds		65,675		-		65,675
Corporate bonds		6,828		-		6,828
U.S. government and agency securities		49,623		-		49,623
	$	126,976	$	-	$	126,976