Note 3 - Revenues From Contracts With Customers and Other Revenues (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 988	$ 5,058	$ 4,813	$ 11,461
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	942	5,058	4,767	11,461
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	46		46
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