Income Taxes - Deferred tax assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss carryforward	$ 493,000	$ 283,000
Allowance for doubtful accounts	14,000	152,000
Revenue recognition	66,000
Less valuation allowance	(573,000)	(435,000)
Net deferred tax asset	$ 0	$ 0