Note 10 - Share-based Compensation (Details) (USD $) | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | |
Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Jun. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Jun. 03, 2010 |
Employee Stock Option [Member] | Employee Stock Option [Member] | Employee Stock Option [Member] | Employee Stock Option [Member] | Employee Stock Option [Member] | Employee Stock Option [Member] | Employee Stock Option [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Restricted Stock Units (RSUs) [Member] | Employee Stock Purchase Plan [Member] | Employee Stock Purchase Plan [Member] | Employee Stock Purchase Plan [Member] | Employee Stock Purchase Plan [Member] | Employee Stock Purchase Plan [Member] |
Begin to Vest [Member] | Options Granted Prior to January 2010 [Member] | Options Granted After January 2010 [Member] | Stock Option Plan [Member] | Stock Option Plan [Member] | Stock Option Plan [Member] | Stock Option Plan [Member] | Maximum [Member] | Stock Option Plan [Member] | Restricted Share Unit Plan [Member] | Restricted Share Unit Plan [Member] | Restricted Share Unit Plan [Member] | Restricted Share Unit Plan [Member] | Restricted Share Unit Plan [Member] | | | | | |
Options Granted Prior to January 2010 [Member] | Stock Option Plan [Member] | Stock Option Plan [Member] | | | | | Restricted Share Unit Plan [Member] | | | | | | | | | | | |
Stock Option Plan [Member] | | | | | | | | | | | | | | | | | | |
Note 10 - Share-based Compensation (Details) [Line Items] | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Maximum Fixed Reloading Percentage | ' | ' | ' | ' | ' | ' | 10.00% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | ' | '1 year | '4 years | '36 months | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | ' | ' | '8 years | '8 years | ' | ' | ' | ' | '5 years | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | ' | ' | ' | 25.00% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Common Stock, Capital Shares Reserved for Future Issuance | ' | ' | ' | ' | 9,155,597 | ' | 9,155,597 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | ' | ' | ' | ' | 2,998,360 | ' | 2,998,360 | ' | ' | ' | 530,910 | ' | ' | 530,910 | ' | 640,910 | ' | 640,910 | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | ' | ' | ' | ' | 104,000 | 10,000 | 185,500 | 10,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Allocated Share-based Compensation Expense (in Dollars) | ' | ' | ' | ' | $400,000 | $400,000 | $1,300,000 | $1,300,000 | ' | ' | ($200,000) | $100,000 | ' | $400,000 | $200,000 | $19,103 | $44,273 | $83,633 | $107,847 | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period | 0 | ' | ' | ' | ' | ' | 1,000 | 0 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period | ' | ' | ' | ' | ' | ' | ' | ' | ' | 0 | 0 | 0 | ' | 110,104 | 22,690 | 0 | 0 | 36,434 | 35,895 | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 900,000 |
Employee Stock Purchase Plan Interval Period | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | '6 months | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 15.00% | ' | 15.00% | ' | ' |
Employee Stock Purchase Plan Maximum Value Of Compensation Per Employee (in Dollars) | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 25,000 | ' | ' |
Employee Stock Purchase Plan Purchase Of Common Stock Percentage | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 85.00% | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 15,000 | ' | ' |
Restricted Stock Unit, Shares Issued Per Unit Upon Conversion | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1 | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 500,000 | ' | ' | ' | ' | ' | ' |
Restricted Share Units Maximum Shares Reserved | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 966,666 | ' | ' | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 0 | 0 | ' | 81,695 | 80,210 | ' | ' | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value (in Dollars) | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | $250,000 | $150,000 | ' | ' | ' | ' | ' |
Value Shares Withheld Restricted Share Unit Percentage | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 25.00% | ' | ' | ' | ' | ' | ' | ' |