Note 3 - Summary of Significant Accounting Policies - Remaining Performance Obligations 2 (Details)	Jun. 30, 2021 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 3,906,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	6 months
Revenue, Remaining Performance Obligation, Amount	$ 839,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 1,185,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 711,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 450,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 721,000
Service [Member]
Revenue, Remaining Performance Obligation, Amount	$ 2,224,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	6 months
Revenue, Remaining Performance Obligation, Amount	$ 690,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 886,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 412,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 151,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 85,000
Clinical Revenue [Member]
Revenue, Remaining Performance Obligation, Amount	$ 205,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	6 months
Revenue, Remaining Performance Obligation, Amount	$ 6,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 160,000
Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Amount	$ 1,477,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	6 months
Revenue, Remaining Performance Obligation, Amount	$ 143,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 286,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	1 year
Revenue, Remaining Performance Obligation, Amount	$ 476,000