v3.8.0.1

Note 11 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Jun. 21, 2013 | Feb. 10, 2011 | Nov. 30, 2009 | Feb. 29, 2008 | Aug. 31, 2006 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2011
Stock Issued During Period, Shares, New Issues |  |  |  |  |  | 5,400,000 |  |  |
Proceeds from Issuance of Common Stock, Net |  |  |  |  |  | $ 15.7 |  |  |
Payments of Stock Issuance Costs |  |  |  |  |  | $ 0.5 |  |  |
Employee Stock Purchase Plan, Shares Issued, Weighted Average Fair Value |  |  |  |  |  | $ 2.59 | $ 2.98 | $ 4.48 |
2006 Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized |  |  |  |  | 342,000 |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized |  |  | 1,400,000 | 375,000 |  |  |  |  |
2006 Equity Incentive Plan [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |
Common Stock Voting Rights Percentage |  |  |  |  | 10.00% |  |  |  |
Fair Value of Common Stock as Percentage of Option Exercise Price |  |  |  |  | 110.00% |  |  |  |
2011 Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized |  |  |  |  |  |  |  |  | 1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Outstanding |  | 52,000 |  |  |  |  |  |  | 1,900,000
Stock Option Plan Option Reserve Annual Increase as Percentage of Outstanding Shares Allowed |  |  |  |  |  |  |  |  | 4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  |  | 4 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant |  |  |  |  |  | 2,368,992 |  |  |
2011 Equity Incentive Plan [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period |  |  |  |  |  |  |  |  | 10 years
Employee Stock Purchase Plan (ESPP) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized |  |  |  |  |  | 250,000 |  |  |
Share-based Payment Award, Number of Shares Authorized |  |  |  |  |  | 2.00% |  |  |
Stock Issued During Period, Shares, Employee Stock Purchase Plans |  |  |  |  |  | 94,893 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant |  |  |  |  |  | 1,041,249 |  |  |
Public Offering [Member] |  |  |  |  |  |  |  |  |
Proceeds from Issuance Initial Public Offering | $ 40.0 |  |  |  |  |  |  |  |

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- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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