Note 10 - Fair Value Accounting - Assets and Liabilities Measured At Fair Value On a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair value, current	$ 1	$ 11,795
Fair Value, Inputs, Level 1 [Member]
Fair value, current	1	1
Fair Value, Inputs, Level 2 [Member]
Fair value, current
Fair Value, Inputs, Level 3 [Member]
Fair value, current		$ 11,794

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26626-111562

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant