Restructuring charges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Restructuring charges
Restructuring charges	$ 283,726	$ 1,227,204
Cash components and activity associated with the realignment of workforce and business under the restructuring program
Balance at beginning of period	195,773
Charges	246,802	1,042,367
Cash Payments	442,575	846,594
Balance at end of period		195,773
Severance and benefits
Cash components and activity associated with the realignment of workforce and business under the restructuring program
Balance at beginning of period	195,773
Charges	218,850	987,994
Cash Payments	414,623	792,221
Balance at end of period		195,773
Legal expenses and other
Cash components and activity associated with the realignment of workforce and business under the restructuring program
Charges	27,952	54,373
Cash Payments	$ 27,952	$ 54,373