Restructuring charges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring charges
Restructuring charges	$ 504,141	$ 283,726	$ 1,227,204
Accelerated Depreciation on abandoned assets	400,000
Cash components and activity associated with the realignment of workforce and business under the restructuring program
Balance at beginning of period	195,773
Charges	246,279	246,802
Cash Payments	233,932	442,575
Balance at end of period	12,347	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	110,996	218,850
Cash Payments	110,172	414,623
Balance at end of period	824	195,773
Legal expenses and other
Cash components and activity associated with the realignment of workforce and business under the restructuring program
Charges	135,283	27,952
Cash Payments	123,760	$ 27,952
Balance at end of period	$ 11,523