INTANGIBLE ASSETS (Schedule of intangible assets) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of finite lived Intangible assets
Intangible assets, Gross	$ 9,550,458	$ 9,531,155
Less: accumulated amortization	(9,337,839)	(9,300,032)
Intangible assets, net	212,619	231,123	$ 262,819
Core Technology [Member]
Summary of finite lived Intangible assets
Intangible assets, Gross	8,567,448	8,567,448
Patents and trademarks [Member]
Summary of finite lived Intangible assets
Intangible assets, Gross	$ 983,010	$ 963,707