Note 2 - Contracts With Customers 2 (Details Textual) - Long-term Contract with Customer [Member]	Mar. 31, 2020 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 759,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Amount	$ 671,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	275 days
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Amount	$ 88,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year