Note 4 - Balance Sheet Components (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation, Total	$ 1,797,000	$ 1,873,000	$ 1,718,000
Accrued Business Exit Costs	150,529
Severance Costs	608,000
Accrued Severance Costs	$ 367,837