Note 17 - Segment Information - Reconciliation of Segment Operating Results (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income from operations		$ 5,719,000	$ 4,877,000	$ 4,563,000
Unallocated corporate, general and administrative expenses*	[1]	(2,075,000)	(2,013,000)	(1,766,000)
Equity-based compensation expenses		(7,631,000)	(6,804,000)	(5,861,000)
Intangible assets amortization expenses		(417,000)	(1,700,000)	(1,700,000)
Losses on available-for-sale marketable securities		1,654,000	1,815,000	1,669,000
Total consolidated income (loss) before taxes		$ (2,750,000)	$ (3,825,000)	$ (3,095,000)

[1] Includes mainly legal, accounting, board of directors and investors relation expenses.