Note 1 - Business and Basis of Presentation (Details Textual)	3 Months Ended
	Dec. 31, 2019 USD ($)	Oct. 01, 2019 USD ($)	Sep. 30, 2019 USD ($)
Number of Reportable Segments	3
Cash and Cash Equivalents, at Carrying Value, Ending Balance	$ 3,156,000		$ 4,308,000
Debt, Current, Total	0	$ 0
Stockholders' Equity Attributable to Parent, Ending Balance	90,200,000
Cash, Uninsured Amount, Foreign	2,000,000
Operating Lease, Liability, Total	540,000
Operating Lease, Right-of-Use Asset	$ 545,000
Operating Lease, Weighted Average Discount Rate, Percent	3.50%	3.50%
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total		$ 636,000
Operating Lease, Right-of-Use Asset		$ 636,000
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities, Total	$ 68,800,000