Summary of acquired identifiable intangible assets (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Acquired Technology
Weighted Average Amortization Period		8
Weighted Average Amortization Period		8
Gross Carrying Amount		$ 17,134,953
Accumulated Amortization		(12,156,049)
Total Value		4,978,904
Weighted Average Amortization Period	8
Gross Carrying Amount	17,036,835
Accumulated Amortization	(14,301,907)
Total Value	2,734,928
Customer Relationships
Weighted Average Amortization Period		8
Weighted Average Amortization Period		8
Gross Carrying Amount		1,000,000
Accumulated Amortization		(708,333)
Total Value		291,667
Weighted Average Amortization Period	8
Gross Carrying Amount	1,000,000
Accumulated Amortization	(833,333)
Total Value	166,667
Total intangible assets
Gross Carrying Amount		18,134,953
Accumulated Amortization		12,864,382
Total Value		5,270,571
Gross Carrying Amount	18,036,835
Accumulated Amortization	(15,135,240)
Total Value	$ 2,901,595