Quarterly report pursuant to Section 13 or 15(d)

Defined contribution plan (Details Textual)

v3.7.0.1
Defined contribution plan (Details Textual) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Defined Contribution Plan, Cost Recognized $ 620,577 $ 419,105 $ 1,125,097 $ 754,663