Note 2 - Contracts With Customers 2 (Details Textual) - Long-term Contract with Customer [Member]	Jun. 30, 2020 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 281,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue, Remaining Performance Obligation, Amount	$ 161,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Amount	$ 120,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year