Note 3 - Summary of Significant Accounting Policies - Remaining Performance Obligations 2 (Details)	Mar. 31, 2021 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 4,225,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	273 days
Revenue, Remaining Performance Obligation, Amount	$ 1,237,000
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	$ 1,103,000
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	$ 451,000
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	$ 723,000
Service [Member]
Revenue, Remaining Performance Obligation, Amount	$ 2,466,000
Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	273 days
Revenue, Remaining Performance Obligation, Amount	$ 1,013,000
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	$ 804,000
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	$ 152,000
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	$ 211,000
Clinical Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	273 days
Revenue, Remaining Performance Obligation, Amount	$ 10,000
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	$ 162,000
Exclusivity Fee [Member]
Revenue, Remaining Performance Obligation, Amount	$ 1,548,000
Exclusivity Fee [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Year)	273 days
Revenue, Remaining Performance Obligation, Amount	$ 214,000
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