CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)
 3 Months Ended 6 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Income Statement [Abstract]        
Revenues $ 2,272,300 $ 2,163,200 $ 4,276,500 $ 4,201,800
Cost of revenues 1,180,800 1,187,500 2,204,600 2,280,400
Gross profit 1,091,500 975,700 2,071,900 1,921,400
Operating Expenses:        
General and administrative 510,100 462,100 1,020,300 878,600
Selling 330,500 248,200 639,600 484,300
Research and development 260,000 109,400 496,600 226,700
Total operating expenses 1,100,600 819,700 2,156,500 1,589,600
Income (loss) from operations (9,100) 156,000 (84,600) 331,800
Other income (expense):        
Interest income 9,200 2,500 9,700 2,800
Other income (expense), net 2,900 (9,300) 2,200 (7,400)
Interest expense 0 (400)   (800)
Total other income (expense), net 12,100 (7,200) 11,900 (5,400)
Income (loss) before income tax expense (benefit) 3,000 148,800 (72,700) 326,400
Income tax expense (benefit):        
Current 0 24,400 0 53,900
Deferred (600) 6,000 (20,100) 12,000
Total income tax expense (benefit) (600) 30,400 (20,100) 65,900
Net income (loss) $ 3,600 $ 118,400 $ (52,600) $ 260,500
Basic earnings (loss) per common share $ 0 $ 0.08 $ (0.04) $ 0.17
Diluted earnings (loss) per common share 0 0.08 (0.04) 0.17
Cash dividends declared per common share $ 0 $ 0.05 $ 0 $ 0.05