Quarterly report pursuant to Section 13 or 15(d)

BALANCE SHEETS (UNAUDITED) (Parenthetical)

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BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($)
Jun. 30, 2021
Dec. 31, 2020
Statement of Financial Position [Abstract]    
Accounts receivable, allowance for doubtful accounts $ 24,469 $ 24,469
Patents, accumulated amortization $ 232,820 $ 199,899
Common stock, par value (in dollars per share) $ 0.01 $ 0.01
Common stock, authorized 75,000,000 75,000,000
Common stock, issued 47,910,676 46,680,119
Common stock, outstanding 44,490,174 43,259,617
Treasury stock 3,420,502 3,420,502