Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities
Net income	$ 85,400	$ 95,800
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation and amortization	1,400	1,800
Deferred income taxes	(54,400)
Non-current assets and liabilities - net	90,300
Cumulative effect of accounting change		96,100
Net income adjusted for non-cash operating activities	122,700	193,700
(Increase) decrease in assets
Accounts receivable	(63,800)	(90,500)
Inventory	(12,600)	2,000
Prepaid and other	6,900	(14,900)
Increase (decrease) in liabilities
Accounts payable and accrued expenses	29,700	(4,900)
Taxes on income	60,300
Deferred revenue		(99,400)
Total increase in operating capital	20,500	(207,700)
Net cash provided by (used in) operating activities	143,200	(14,000)
Increase (decrease) in cash	143,200	(14,000)
Cash at beginning of year	400,800	360,400
Cash at end of period	544,000	346,400
Supplemental Disclosure of Non Cash Lease Activities
Operating lease right of use - building	241,100
Operating lease liability	$ (241,100)