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Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended	12 Months Ended		204 Months Ended
	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Jan. 01, 2019
Marketable Securities, Unrealized Gain (Loss), Total		$ 34,000	$ (113,000)
Marketable Securities, Total			349,000
Cost-method Investments, Other than Temporary Impairment			363,000
Cost Method Investments		3,081,000	760,000	$ 3,081,000
Share-based Payment Arrangement, Expense		$ 191,000	$ 62,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		42,000	12,000	1,356,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 16.15	$ 4.86
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 414,000		$ 414,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total					$ 1,258,000
Operating Lease, Right-of-Use Asset					$ 1,258,000
The 2011 Non-employee Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		12,000	12,000
The 2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		30,000	0
Lumense Inc. [Member]
Cost-method Investments, Other than Temporary Impairment	$ 250,000	$ 0	$ 250,000
General and Administrative Expense [Member]
Depreciation, Total		$ 1,012,000	$ 614,000