Amortization expense for acquired identifiable intangible assets (Details) (USD $)	Dec. 31, 2013
Amortization expense for acquired identifiable intangible assets
Amortization expense for acquired identifiable intangible assets for 2011 in millions	2.3
Amortization expense for acquired identifiable intangible assets for 2012 in millions	2.3
Amortization expense for acquired identifiable intangible assets for 2013 in millions	2.3
Amortization expense for acquired identifiable intangible assets for 2014	$ 2,263,776
Amortization expense for acquired identifiable intangible assets for 2015	637,819
Total Amortization expense for acquired identifiable intangible assets for 2014 and 2015	$ 2,901,595