Note 3 - Contracts With Customers 2 (Details Textual)	Dec. 31, 2018 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 976,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Amount	$ 881,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Amount	$ 95,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year