Note 3 - Short-term and Long-term Investments (Tables)

6 Months Ended

Jun. 30, 2016

Available-for-sale Securities [Table Text Block]

	Cost		Unrealized Gains		Unrealized Losses			Other- Than- Temporary Impairment Losses		Fair Value		Cash and Cash Equivalents		Short-term Investments			Long-term Investments
Cash	$	40,571	$	-	$	-		$	-	$	40,571	$	40,571	$	-		$	-
Money market securities		27,964		-		-			-		27,964		27,964		-			-
Certificates of deposit		26,600		-		-			-		26,600		-		18,467			8,133
Marketable securities:
Corporate securities		35,048		27		(6	)		-		35,069		-		26,102			8,967
Federal agency securities		16,592		3		(1	)		-		16,594		-		10,594			6,000
Municipal securities		46,851		63		(2	)		-		46,912		755		33,918			12,239
Total marketable securities		98,491		93		(9	)		-		98,575		755		70,614			27,206
																`
	$	193,626	$	93	$	(9	)	$	-	$	193,710	$	69,290	$	89,081		$	35,339

	Cost		Unrealized Gains		Unrealized Losses			Other- Than- Temporary Impairment Losses		Fair Value		Cash and Cash Equivalents		Short-term Investments		Long-term Investments
Cash	$	55,987	$	-	$	-		$	-	$	55,987	$	55,987	$	-	$	-
Money market securities		20,373		-		-			-		20,373		20,373		-		-
Certificates of deposit		26,223		-		-			-		26,223		-		16,637		9,586
Marketable securities:
Corporate securities		27,186		-		(68	)		-		27,118		1,621		19,181		6,316
Federal agency securities		18,823		-		(65	)		-		18,758		-		10,129		8,629
Municipal securities		53,870		16		(35	)		-		53,851		1,534		33,629		18,688
Total marketable securities		99,879		16		(168	)		-		99,727		3,155		62,939		33,633

	$	202,462	$	16	$	(168	)	$	-	$	202,310	$	79,515	$	79,576	$	43,219

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

	June 30, 2016				December 31, 2015
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Marketable securities:
Due in one year or less	$	71,342	$	71,368	$	66,148	$	66,094
Due after one year through 5 years		27,149		27,207		33,731		33,633
Due after 5 years through 10 years		-		-		-		-
Due after 10 years		-		-		-		-

	$	98,491	$	98,575	$	99,879	$	99,727

Schedule of Unrealized Loss on Investments [Table Text Block]

	June 30, 2016									December 31, 2015
	Less Than 12 Months					Greater Than 12 Months				Less Than 12 Months					Greater Than 12 Months
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Marketable securities:
Corporate securities	$	14,577	$	(6	)	$	-	$	-	$	25,137	$	(68	)	$	-	$	-
Federal agency securities		6,566		(1	)		-		-		18,759		(65	)		-		-
Municipal securities		8,626		(2	)		-		-		22,981		(35	)		-		-

	$	29,769	$	(9	)	$	-	$	-	$	66,877	$	(168	)	$	-	$	-

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details