Note 7 - Income Taxes - Net Deferred Tax Assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Federal, state and foreign loss carryforwards		$ 794,000
Deferred revenue	23,000	11,000
Federal and state tax credits	294,000	757,000
Other	438,000	402,000
Total deferred tax asset	755,000	1,964,000
Less valuation allowance	(475,000)	(1,964,000)
Net deferred tax asset	$ 280,000