Note 12 - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Auction Rate Securities [Member]
Balance	$ (276)	$ (217)	$ (209)		$ (209)
Other comprehensive income (loss) before reclassifications	88	(59)	(8)
Amounts reclassified from accumulated other comprehensive income
Net current period other comprehensive income (loss)	88	(59)	(8)
Balance	(188)	(276)	(217)		(188)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Available-for-sale Securities [Member]
Balance	104	52	(166)		(166)
Other comprehensive income (loss) before reclassifications	(98)	53	220
Amounts reclassified from accumulated other comprehensive income	(3)	(1)	(2)
Net current period other comprehensive income (loss)	(101)	52	218
Balance	3	104	52		3
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	300	2,339	1,841		1,841
Other comprehensive income (loss) before reclassifications	(52)	(2,039)	498
Amounts reclassified from accumulated other comprehensive income
Net current period other comprehensive income (loss)	(52)	(2,039)	498
Balance	248	300	2,339		248
Balance	128	2,174	1,466		1,466
Other comprehensive income (loss) before reclassifications	(62)	(2,045)	710
Amounts reclassified from accumulated other comprehensive income	(3)	(1)	(2)
Net current period other comprehensive income (loss)	(65)	(2,046)	708	$ (3,102)	(1,403)	$ (2,727)
Balance	$ 63	$ 128	$ 2,174		$ 63