Note 12 - Leases (Details Textual)			1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 02, 2020 USD ($)	Jun. 01, 2020 GBP (£)	Mar. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)	Dec. 31, 2019 USD ($)
Operating Lease, Expense				$ 18,000	$ 23,000	$ 50,000	$ 65,000
Operating Lease, Right-of-Use Asset				$ 7,317,000		$ 7,317,000				$ 7,443,000
Lease of Property at 94C Milton Park, Abingdon, U.K. [Member]
Lessee, Operating Lease, Renewal Term (Year)		2 years
Lessee, Operating Lease, Penalty-free Termination Notice Period (Month)		3 months
Operating Lease, Right-of-Use Asset | £		£ 194,000
Operating Lease, Liability, Total | £		£ 175,000
Lease of Property at 94C Milton Park, Abingdon, U.K. [Member] | Forecast [Member]
Operating Lease, Expense | £								£ 256,980	£ 128,490
Property at 320 Norwood Park, South Norwood Massachusetts [Member]
Lessee, Operating Lease, Renewal Term (Year)	15 months
Operating Lease, Right-of-Use Asset	$ 251,000
Operating Lease, Liability, Total	234,000
Operating Leases, Annual Rent Expense	$ 213,000
Minimum [Member]
Operating Leases, Monthly Rent Expense			$ 30,000
Maximum [Member]
Operating Leases, Monthly Rent Expense			$ 38,000