Note 12 - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Auction Rate Securities [Member]
Balance	$ (217)	$ (209)		$ (209)
Other comprehensive income (loss) before reclassifications	(59)	(8)
Net current period other comprehensive income (loss)	(59)	(8)
Balance	(276)	(217)		(276)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Available-for-sale Securities [Member]
Balance	52	(166)		(166)
Other comprehensive income (loss) before reclassifications	53	220
Amounts reclassified from accumulated other comprehensive income	(1)	(2)
Net current period other comprehensive income (loss)	52	218
Balance	104	52		104
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	2,339	1,841		1,841
Other comprehensive income (loss) before reclassifications	(2,039)	498
Net current period other comprehensive income (loss)	(2,039)	498
Balance	300	2,339		300
Balance	2,174	1,466		1,466
Other comprehensive income (loss) before reclassifications	(2,045)	710
Amounts reclassified from accumulated other comprehensive income	(1)	(2)
Net current period other comprehensive income (loss)	(2,046)	708	$ 90	(1,338)	$ 375
Balance	$ 128	$ 2,174		$ 128