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Note 8 - Line of Credit (Details Textual) - USD ($) $ in Thousands |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | ---
Oct. 26, 2015 | Oct. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Line of Credit Facility, Maximum Borrowing Capacity | $ 60,000 |  | $ 100,000 |  |
Interest Expense, Debt |  | $ 400 | 500 | $ 500 | $ 1,300
Interest Costs Capitalized |  |  |  | 0 | $ 100
2015 Credit Agreement [Member] |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  | 19,100 |  |
Long-term Line of Credit |  |  | $ 0 | $ 0 |
2015 Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 1.75% |  |  |  |
2015 Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 2.25% |  |  |  |
2015 Credit Agreement [Member] | Prime Rate [Member] | Minimum [Member] |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 0.75% |  |  |  |
2015 Credit Agreement [Member] | Prime Rate [Member] | Maximum [Member] |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 1.25% |  |  |  |

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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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- Definition Amount of interest capitalized during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 + Details
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- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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