Note 3 - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash equivalents:
Cash Equivalents	$ 1,343	$ 1,000
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]
Cash equivalents:
Cash Equivalents	1,343	1,000
Fair Value, Measurements, Recurring [Member] \| Commercial Paper [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash equivalents:
Cash Equivalents	549	38
Fair Value, Measurements, Recurring [Member] \| Commercial Paper [Member]
Cash equivalents:
Cash Equivalents	549	38
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable investments:
Total assets at fair value	1,343	1,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable investments:
Available-for-sale securities	35,902	37,539
Total assets at fair value	36,451	37,577
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable investments:
Total assets at fair value
Fair Value, Measurements, Recurring [Member]
Marketable investments:
Available-for-sale securities	35,902	37,539
Total assets at fair value	37,794	38,577
Money Market Funds [Member]
Cash equivalents:
Cash Equivalents	1,343	1,000
Commercial Paper [Member]
Cash equivalents:
Cash Equivalents	549	38
Cash Equivalents	7,420	10,868
Marketable investments:
Available-for-sale securities	$ 35,902	$ 37,539

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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- References

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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- References

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