Note 6 - Marketable Securities - Short-term and Long-term Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Unrealized Losses	$ (319)	$ (497)
Fair Value	117,415	123,475
Amortized Cost	117,707	123,956
Unrealized Gains	27	16
Bank Time Deposits [Member]
Unrealized Losses	(26)	(22)
Fair Value	6,914	7,172
Amortized Cost	6,937	7,182
Unrealized Gains	3	12
US States and Political Subdivisions Debt Securities [Member]
Unrealized Losses	(59)	(187)
Fair Value	38,485	46,392
Amortized Cost	38,522	46,578
Unrealized Gains	22	1
Corporate Debt Securities [Member]
Unrealized Losses	(98)	(147)
Fair Value	33,803	38,345
Amortized Cost	33,899	38,490
Unrealized Gains	2	2
US Government Agencies Debt Securities [Member]
Unrealized Losses	(136)	(141)
Fair Value	38,212	31,566
Amortized Cost	38,349	31,706
Unrealized Gains		$ 1

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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