Note 12 - Revenue - Remaining Performance Obligations 2 (Details)	Dec. 31, 2022 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 4,128,000
Service [Member]
Revenue, Remaining Performance Obligation, Amount	2,038,000
Device Revenue [Member]
Revenue, Remaining Performance Obligation, Amount	886,000	[1]
Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Amount	1,047,000
Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Amount	$ 157,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 2,301,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Service [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 1,157,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Device Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 845,000	[1]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 977,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Service [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 637,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Device Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 41,000	[1]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 543,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Service [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 244,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Device Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 0	[1]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 307,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 | Service [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 | Device Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 0	[1]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 | Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 189,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 | Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 118,000

[1] Represents the minimum purchase requirements under the distribution agreement the Company signed with its AXP distributor in China and other revenue deferred at December 31, 2022.