Note 3 - Revenues From Contracts With Customers and Other Revenues (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 192	$ 6,104	$ 5,005	$ 17,565
Contract with Customer, Asset, after Allowance for Credit Loss, Total	0		0		$ 0
Contract with Customer, Asset, Credit Loss Expense (Reversal)			0		0
Transferred at Point in Time [Member]
Revenue from Contract with Customer, Including Assessed Tax	122	6,104	4,889	17,565
Transferred at Point in Time [Member] | Variable Consideration or Multiple Performance Obligations [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0	0
Revenue, Remaining Performance Obligation, Amount	0		0		0
Transferred over Time [Member]
Revenue from Contract with Customer, Including Assessed Tax	70		116
Transferred over Time [Member] | Variable Consideration or Multiple Performance Obligations [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	$ 0	0	$ 0
Revenue, Remaining Performance Obligation, Amount	$ 0		$ 0		$ 0