Note 7 - Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2014

Investments Schedule [Abstract]

Held-to-maturity Securities [Table Text Block]

	June 30, 2014
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities	$	16,453	$	3	$	(20	)	$	16,436
Corporate debt securities		28,752		21		(35	)		28,738
Commercial paper		1,998		-		-			1,998
U.S. municipal securities		30,222		69		(2	)		30,289
Certificates of deposit/time deposits		5,155		9		(2	)		5,162
Total marketable securities	$	82,580	$	102	$	(59	)	$	82,623

	December 31, 2013
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities	$	21,713	$	2	$	(22	)	$	21,693
Corporate debt securities		29,480		30		(20	)		29,490
U.S. municipal securities		44,474		49		(22	)		44,501
Certificates of deposit/time deposits		4,695		5		(8	)		4,692
Total marketable securities	$	100,362	$	86	$	(72	)	$	100,376

Investments Classified by Contractual Maturity Date [Table Text Block]

(in thousands)	June 30, 2014
Due in one year or less	$	25,255
Due after one year through five years		57,325
Total marketable securities	$	82,580