Note 6 - Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	[1]
Federal income tax liability (benefit) at statutory rate		$ 85,599	$ (101,578)
State income tax liability (benefit), net of federal income tax effect		20	(9,518)
(Decrease) increase in valuation allowance		(328,541)	2,266,219
Stock-based compensation			91,179
Adjustment to deferred tax assets		189,186
Remeasurement of deferred income taxes	$ 713,826		713,826
Other		27,233	81,716
Total income tax (benefit) provision		$ (26,503)	$ 3,041,844	[2],[3]

[1] As adjusted for the retrospective adoption of ASC 606

[2] As adjusted for the retrospective adoption of ASC 606

[3] As adjusted for the retrospective adoption of ASC 606