Schedule II - Valuation and Qualifying Accounts - Valuation and Qualifying Accounts (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Balance Beginning of Year		$ 3,549,797	$ 1,694,375
Charges to Costs and Expenses		(308,344)	2,262,907
Deductions	[1]	(1,171,798)	(407,485)
Balance End of Year		2,069,655	3,549,797
Inventory Valuation Reserve [Member]
Balance Beginning of Year		1,421,345	606,504
Charges to Costs and Expenses		(206,155)	802,966
Deductions	[1]	193,884	11,875
Balance End of Year		1,409,074	1,421,345
Allowance for Doubtful Accounts [Member]
Balance Beginning of Year		2,128,452	1,087,871
Charges to Costs and Expenses		(102,189)	1,437,949
Deductions	[1]	(1,365,682)	(397,368)
Balance End of Year		$ 660,581	$ 2,128,452

[1] Includes write-offs, the impact of foreign currency exchange rates.