Note 7 - Goodwill and Acquired Intangible Assets - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Gross carrying amount	$ 664	$ 680
Accumulated amortization	594	593
Net carrying amount	70	87
Other Intangible Assets [Member]
Gross carrying amount	664	680
Accumulated amortization	594	593
Net carrying amount	$ 70	$ 87
Other Intangible Assets [Member] | Minimum [Member]
Amortization period (Year)	5 years	5 years
Other Intangible Assets [Member] | Maximum [Member]
Amortization period (Year)	10 years	10 years