Summary of significant accounting policies (Details Textual) - shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Summary Of Significant Accounting Policies [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)	10,451	9,845
Warrant [Member]
Summary Of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,020,825	1,020,825
Restricted Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	9,000	130,000