Note 9 - Leases (Details Textual)	1 Months Ended				12 Months Ended
	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 01, 2019	Feb. 01, 2017 USD ($) ft²
Operating Lease, Expense					$ 280,000	$ 300,000
Operating Lease, Weighted Average Remaining Lease Term (Month)					27 months
Operating Lease, Weighted Average Discount Rate, Percent					12.50%
Operating Lease, Property Plant and Equipment, Amount					$ 464,000
Sublease Agreement for Relocation of Headquarters [Member]
Area of Real Estate Property (Square Foot) | ft²								12,400
Lessee, Operating Lease, Renewal Term (Year)		34 months					1 year
Operating Leases, Monthly Rent Per Rentable Square Foot During First Year								20.50
Operating Leases, Monthly Rent Per Rentable Square Foot During Second Year								21.12
Operating Leases, Monthly Rent Per Rentable Square Foot During Third Year								21.75
Security Deposit								$ 22,000
Operating Leases, Allowance for Certain Improvements								$ 88,000
Lessee, Operating Lease, Rent Abatement	$ 19,000
Sublease Agreement for Relocation of Headquarters First Year Extension [Member]
Lessee, Operating Lease, Monthly Gross Rent		$ 21,028
Sublease Agreement for Relocation of Headquarters Second Year Extension [Member]
Lessee, Operating Lease, Monthly Gross Rent		21,643
Sublease Agreement for Relocation of Headquarters Third Year Extension [Member]
Lessee, Operating Lease, Monthly Gross Rent		$ 22,258
Noncancelable Operating Lease Agreement for Office Equipment [Member]
Lessee, Operating Lease, Term of Contract (Month)			36 months	36 months
Operating Leases, Monthly Payment			$ 2,000	$ 3,000
Leases of Viveve Systems [Member]
Lessor, Operating Lease, Depreciation on Leased Assets					$ 325,000	$ 462,000