Quarterly report pursuant to Section 13 or 15(d)

Stock options and warrants (Schedule of Stock-based Compensation) (Details)

v2.4.1.9
Stock options and warrants (Schedule of Stock-based Compensation) (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]    
Stock-based compensation $ 433,402us-gaap_AllocatedShareBasedCompensationExpense $ 403,021us-gaap_AllocatedShareBasedCompensationExpense
Selling, general and administrative expenses [Member]    
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]    
Stock-based compensation 392,362us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SellingGeneralAndAdministrativeExpensesMember
382,994us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SellingGeneralAndAdministrativeExpensesMember
Research and development expenses [Member]    
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]    
Stock-based compensation $ 41,040us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ResearchAndDevelopmentExpenseMember
$ 20,027us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ResearchAndDevelopmentExpenseMember