Stock options and warrants (Schedule of Stock-based Compensation) (Details) - USD ($) |
3 Months Ended | |
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Mar. 31, 2016 |
Mar. 31, 2015 |
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| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock-based compensation | $ 47,884 | $ 433,402 |
| Selling, General and Administrative Expenses [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock-based compensation | 45,324 | 392,362 |
| Research and Development Expense [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock-based compensation | $ 2,560 | $ 41,040 |
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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