Note 14 - Net Loss Per Share of Common Stock - Computation of Basic and Diluted Net Loss Per Share of Common (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Net loss | $ (9,885) | $ (13,013) | $ (13,059) | $ (15,551) | $ (9,682) | $ (11,402) | $ (11,092) | $ (10,981) | $ (51,508) | $ (43,157) | $ (24,399) |
| Adjustments for change in fair value of warrant liability | (2,120) | ||||||||||
| Diluted | $ (51,508) | $ (43,157) | $ (26,519) | ||||||||
| Shares used in computing net loss per share of common stock, basic (in shares) | 46,883,535 | 45,313,118 | 44,300,099 | ||||||||
| Dilutive effect of warrants (in shares) | 168,341 | ||||||||||
| Diluted (in shares) | 46,883,535 | 45,313,118 | 44,468,440 | ||||||||
| Net loss per share of common stock, basic (in dollars per share) | $ (0.20) | $ (0.28) | $ (0.29) | $ (0.34) | $ (0.21) | $ (0.25) | $ (0.24) | $ (0.24) | $ (1.10) | $ (0.95) | $ (0.55) |
| Net loss per share of common stock, diluted (in dollars per share) | $ (0.20) | $ (0.28) | $ (0.29) | $ (0.34) | $ (0.21) | $ (0.25) | $ (0.24) | $ (0.25) | $ (1.10) | $ (0.95) | $ (0.60) |
| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of expense (income) related to adjustment to fair value of warrant liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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