Note 1 - Organization and Significant Accounting Policies - Summary of Remaining Performance Obligations 2 (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Rental Revenue [Member]
Revenue, expected to be recognized in the future	$ 14,799
Service Revenue [Member]
Revenue, expected to be recognized in the future	108
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Rental Revenue [Member]
Revenue, expected to be recognized in the future	$ 10,151
Revenue, expected to be recognized in the future, period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Service Revenue [Member]
Revenue, expected to be recognized in the future	$ 67
Revenue, expected to be recognized in the future, period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Rental Revenue [Member]
Revenue, expected to be recognized in the future	$ 3,748
Revenue, expected to be recognized in the future, period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Service Revenue [Member]
Revenue, expected to be recognized in the future	$ 31
Revenue, expected to be recognized in the future, period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Rental Revenue [Member]
Revenue, expected to be recognized in the future	$ 900
Revenue, expected to be recognized in the future, period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Service Revenue [Member]
Revenue, expected to be recognized in the future	$ 10
Revenue, expected to be recognized in the future, period (Year)	1 year