Note 3 - Contracts With Customers 2 (Details Textual) - Long-term Contract with Customer [Member]	Dec. 31, 2019 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 1,097,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Amount	$ 1,037,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Amount	$ 60,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year