Note 1 - Summary of Significant Accounting Policies (Details Textual) - EUR (€) € / shares in Units, € in Thousands | Apr. 26, 2016 | Apr. 14, 2016 | May 28, 2013 | Jan. 18, 2013 | Mar. 28, 2012 | Jun. 25, 2010 | Oct. 29, 2007 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | Feb. 18, 2016 | Dec. 31, 2013 | Dec. 19, 2012 | Jun. 24, 2010 | Dec. 31, 2007 | May 22, 2007 |
Product Warranty Expense | | | | | | | | € 319 | € 354 | € 429 | | | | | | |
Research Tax Credit | | | | | | | | 511 | 448 | 518 | | | | | | |
Advertising Expense | | | | | | | | € 744 | € 461 | € 413 | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | | 575,000 | 0 | 0 | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | | | € 605 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 360 | € 66 | € 140 | | | | | | |
Maintenance Contracts, Useful Life | | | | | | | | 1 year | | | | | | | | |
Patents [Member] | | | | | | | | | | | | | | | | |
Finite-Lived Intangible Asset, Useful Life | | | | | | | | 5 years | | | | | | | | |
Licensing Agreements [Member] | | | | | | | | | | | | | | | | |
Finite-Lived Intangible Asset, Useful Life | | | | | | | | 5 years | | | | | | | | |
Trademarks and Trade Names [Member] | | | | | | | | | | | | | | | | |
Finite-Lived Intangible Asset, Useful Life | | | | | | | | 7 years | | | | | | | | |
The 2007 Plan [Member] | | | | | | | | | | | | | | | | |
Common Stock, Shares Subscribed but Unissued | | | | | | | | | | | | | | | | 600,000 |
The 2010 Plan [Member] | | | | | | | | | | | | | | | | |
Common Stock, Shares Subscribed but Unissued | | | | | | | | | | | | | | 229,100 | | |
The 2012 Plan [Member] | | | | | | | | | | | | | | | | |
Common Stock, Shares Subscribed but Unissued | | | | | | | | | | | | | 500,000 | | | |
The 2016 Plan [Member] | | | | | | | | | | | | | | | | |
Common Stock, Shares Subscribed but Unissued | | | | | | | | | | | 1,000,000 | | | | | |
Employee Stock Option [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | | 575,000 | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | 4 years 120 days | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 1,427,438 | 917,188 | 1,095,850 | | 1,310,850 | | | | |
Employee Stock Option [Member] | The 2007 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | | | | | | | | | | | | | | | | 600,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 95,912 | 504,088 | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 377,838 | | | | | | | | |
Employee Stock Option [Member] | The 2007 Plan [Member] | October 29, 2007 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | 504,088 | | | | | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price | | | | | | | € 3.99 | | | | | | | | | |
Equity Restrictions, Term of Holding Before Sale of Stock | | | | | | | 4 years | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | | 10 years | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | | | | | | | | | | € 1,731 | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 4 years | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 327,838 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 0 | € 0 | € 0 | | | | | | |
Employee Stock Option [Member] | The 2007 Plan [Member] | June 25, 2010 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 95,912 | | | | | | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price | | | | | | € 1.88 | | | | | | | | | | |
Equity Restrictions, Term of Holding Before Sale of Stock | | | | | | 4 years | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | 10 years | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | € 143 | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | 4 years | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 50,000 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 0 | 0 | 8 | | | | | | |
Employee Stock Option [Member] | The 2010 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | | | | | | | | | | | | | | 229,100 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 229,100 | | | | | | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price | | | | | | € 2.38 | | | | | | | | | | |
Equity Restrictions, Term of Holding Before Sale of Stock | | | | | | 4 years | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | 10 years | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | | | | | | | | | € 328 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | 4 years | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 127,100 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 0 | 0 | 4 | | | | | | |
Employee Stock Option [Member] | The 2012 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | | | | | | | | | | | | | 500,000 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | 500,000 | | | | | | | | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price | | | | € 1.91 | | | | | | | | | | | | |
Equity Restrictions, Term of Holding Before Sale of Stock | | | | 4 years | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | 10 years | | | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | | | | | | | € 660 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | 4 years | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 362,500 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 29 | € 66 | € 128 | | | | | | |
Employee Stock Option [Member] | The 2016 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | | | | | | | | | | | 1,000,000 | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | 575,000 | | | | | | | | | | | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price | € 3.22 | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | 10 years | | | | | | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | | | | | | | | € 331 | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | 4 years | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | | | | 560,000 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | € 331 | | | | | | | | |
American Depository Shares (ADS) [Member] | Private Placement [Member] | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues | | 3,283,284 | 3,000,000 | | 2,812,500 | | | | | | | | | | | |
Maximum [Member] | | | | | | | | | | | | | | | | |
Standard Product Warranty Period | | | | | | | | 2 years | | | | | | | | |
Maximum [Member] | Employee Stock Option [Member] | The 2007 Plan [Member] | October 29, 2007 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | 4 years | | | | | | | | | |
Maximum [Member] | Employee Stock Option [Member] | The 2007 Plan [Member] | June 25, 2010 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 4 years | | | | | | | | | | |
Maximum [Member] | Employee Stock Option [Member] | The 2010 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 4 years | | | | | | | | | | |
Maximum [Member] | Employee Stock Option [Member] | The 2012 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | 4 years | | | | | | | | | | | | |
Maximum [Member] | Employee Stock Option [Member] | The 2016 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 4 years | | | | | | | | | | | | | | | |
Minimum [Member] | | | | | | | | | | | | | | | | |
Standard Product Warranty Period | | | | | | | | 1 year | | | | | | | | |
Minimum [Member] | Employee Stock Option [Member] | The 2007 Plan [Member] | October 29, 2007 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | 1 year | | | | | | | | | |
Minimum [Member] | Employee Stock Option [Member] | The 2007 Plan [Member] | June 25, 2010 Award [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 1 year | | | | | | | | | | |
Minimum [Member] | Employee Stock Option [Member] | The 2010 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 1 year | | | | | | | | | | |
Minimum [Member] | Employee Stock Option [Member] | The 2012 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | 1 year | | | | | | | | | | | | |
Minimum [Member] | Employee Stock Option [Member] | The 2016 Plan [Member] | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 1 year | | | | | | | | | | | | | | | |
Devices Leased Under RPPs and Devices Subject to Sale and Leaseback Transactions [Member] | Maximum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 7 years | | | | | | | | |
Leasehold Improvements [Member] | Maximum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 10 years | | | | | | | | |
Equipment [Member] | Maximum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 10 years | | | | | | | | |
Equipment [Member] | Minimum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 3 years | | | | | | | | |
Furniture, Fixtures, Fittings, and Other [Member] | Maximum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 10 years | | | | | | | | |
Furniture, Fixtures, Fittings, and Other [Member] | Minimum [Member] | | | | | | | | | | | | | | | | |
Property, Plant and Equipment, Useful Life | | | | | | | | 2 years | | | | | | | | |