Note 2 - Acquisitions and Divestitures (Details Textual) € in Millions								3 Months Ended			6 Months Ended	12 Months Ended
	Jun. 22, 2020 USD ($)	Oct. 11, 2019 USD ($)	Jul. 12, 2019 USD ($)	Oct. 22, 2018 USD ($)	Oct. 22, 2018 EUR (€)	Sep. 20, 2018 USD ($)	Apr. 05, 2018 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Oct. 22, 2018 EUR (€)
Goodwill, Purchase Accounting Adjustments												$ (1,345,000)	$ 0
Reddick Divestiture [Member]
Proceeds from Sale of Productive Assets, Total							$ 7,400,000
Long-term Purchase Commitment, Period (Year)							2 years
Gain (Loss) on Disposition of Assets for Financial Service Operations, Total										$ 5,900,000
Artegraft Inc [Member]
Payments to Acquire Businesses, Gross	$ 72,500,000
Escrow Deposit Disbursements Related to Property Acquisition	$ 7,500,000
Business Combination, Contingent Consideration, Liability, Total											$ 400,000	400,000
Business Acquisition, Purchase Price Allocation, Goodwill Expected Tax Deductible, Period (Year)	15 years
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)	12 years 7 months 6 days
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual											11,100,000
Artegraft Inc [Member] | First Earn-out [Member]
Business Combination, Contingent Consideration, Liability, Total	$ 5,800,000
Business Combination, Contingent Consideration, Unit Sales	20,000
Artegraft Inc [Member] | Second Earn-out [Member]
Business Combination, Contingent Consideration, Liability, Total	$ 5,800,000
Business Combination, Contingent Consideration, Unit Sales	24,000
Artegraft Inc [Member] | Third Earn-out [Member]
Business Combination, Contingent Consideration, Liability, Total	$ 5,800,000
Business Combination, Contingent Consideration, Unit Sales	28,800
Artegraft Inc [Member] | Catch-Up Payment [Member]
Business Combination, Contingent Consideration, Liability, Total	$ 400,000
Business Combination, Contingent Consideration, Minimum Unit Sales in Three Years	58,240
Business Combination, Contingent Consideration, Minimum Unit Sales in Three Years, Percent of Combined Individual Year Targets	80.00%
Business Combination, Contingent Consideration, Before Multiplied by Fraction	$ 17,500,000
Business Combination, Contingent Consideration, Denominator, Less Amount Paid	72,800
Artegraft Inc [Member] | Maximum [Member]
Business Combination, Consideration Transferred, Total	$ 90,000,000.0
CardioCel and VascuCel Biologic Patches [Member]
Payments to Acquire Businesses, Gross		$ 14,200,000
Business Combination, Contingent Consideration, Liability, Total		7,500,000									$ 2,300,000	$ 2,300,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)												10 years 4 months 24 days
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual									$ 1,400,000
Goodwill, Purchase Accounting Adjustments								$ (1,300,000)
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets								$ 1,300,000
CardioCel and VascuCel Biologic Patches [Member] | Technology Licenses [Member]
Business Combination, Consideration Transferred, Total		8,000,000.0
CardioCel and VascuCel Biologic Patches [Member] | Achieving Audited Financial Statements of Acquired Business [Member]
Payments to Acquire Businesses, Gross		300,000
CardioCel and VascuCel Biologic Patches [Member] | First Holdback [Member]
Business Combination, Contingent Consideration, Liability, Total		700,000
CardioCel and VascuCel Biologic Patches [Member] | Third Holdback [Member]
Business Combination, Contingent Consideration, Liability, Total		2,000,000.0
CardioCel and VascuCel Biologic Patches [Member] | Revenues Exceeding Twenty Million in the First Twelve Month Period After Closing Date [Member]
Business Combination, Contingent Consideration, Liability, Total		2,500,000
CardioCel and VascuCel Biologic Patches [Member] | Revenues Exceeding Fifteen Million in the First Twelve Month Period After Closing Date [Member]
Business Combination, Contingent Consideration, Liability, Total		1,200,000
CardioCel and VascuCel Biologic Patches [Member] | Revenues Exceeding Thirty Million in the Second Twelve Month Period After Closing Date [Member]
Business Combination, Contingent Consideration, Liability, Total		2,500,000
CardioCel and VascuCel Biologic Patches [Member] | Revenues Exceeding Twenty-Two and a Half Million in the First Twelve Month Period After Closing Date [Member]
Business Combination, Contingent Consideration, Liability, Total		1,200,000
CardioCel and VascuCel Biologic Patches [Member] | Extension of Product Shelf Life from 36 Months to 60 Months in the First Anniversary of Closing Date [Member]
Business Combination, Contingent Consideration, Liability, Total		500,000
CardioCel and VascuCel Biologic Patches [Member] | Maximum [Member] | Biological Patch Business Assets [Member]
Business Combination, Consideration Transferred, Total		$ 15,300,000
Tru-Incise Valve Cutter [Member]
Business Combination, Consideration Transferred, Total			$ 8,000,000.0
Payments to Acquire Businesses, Gross			$ 6,800,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)			11 years 9 months 18 days
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual													$ 800,000
Business Combination, Deferred Purchase Consideration, Installment Payment			$ 400,000
Business Combination, Deferred Purchase Consideration			1,200,000
Acquisition Date Fair Value			$ 1,100,000
Business Combination ,Fair Value Inputs, Discount Rate			4.19%
Cardial [Member]
Business Combination, Consideration Transferred, Total				$ 2,300,000	€ 2.0
Payments to Acquire Businesses, Gross				$ 1,300,000	€ 1.1
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)				9 years 4 months 24 days	9 years 4 months 24 days
Business Combination, Deferred Purchase Consideration				$ 400,000										€ 0.4
Business Combination, Consideration Transferred, Liabilities Incurred				500,000	€ 0.5
Deferred Tax Assets, Business Combinations				600,000										€ 0.5
Business Combination, Bargain Purchase, Gain Recognized, Amount				$ 1,600,000	€ 1.4
Applied Medical [Member]
Business Combination, Consideration Transferred, Total						$ 14,200,000
Business Acquisition, Purchase Price Allocation, Goodwill Expected Tax Deductible, Period (Year)						15 years
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)						13 years
Acquisition Date Fair Value						$ 3,000,000.0
Business Combination ,Fair Value Inputs, Discount Rate						3.75%
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Current Assets Deferred Costs						$ 3,200,000
Applied Medical [Member] | Closing Date [Member]
Business Combination, Consideration Transferred, Total						11,000,000.0
Applied Medical [Member] | 12 Months Following the Closing Date [Member]
Business Combination, Consideration Transferred, Total						2,000,000.0
Applied Medical [Member] | 24 Months Following the Closing Date [Member]
Business Combination, Consideration Transferred, Total						$ 1,200,000
Balloon Supply Agreement [Member] | Reddick Divestiture [Member]
Long-term Purchase Commitment, Period (Year)							6 years