Note 10 - Commitments and Contingencies (Details Textual) $ in Thousands, € in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Business Combination, Contingent Consideration, Liability, Total	$ 4,193			$ 3,936
Operating Lease, Weighted Average Discount Rate, Percent	7.90%			8.20%
Operating Lease, Right-of-Use Asset	$ 4,234			$ 1,164
Operating Lease, Liability, Total	4,379
Operating Lease, Liability, Current	800
Operating Lease, Liability, Noncurrent	3,640			$ 628
Operating Lease, Cost	$ 400		$ 400
Operating Lease, Weighted Average Remaining Lease Term (Year)	9 years
Operating Lease, Payments	$ 400		400
Minimum [Member]
Lessee, Operating Lease, Discount Rate	6.10%
Maximum [Member]
Lessee, Operating Lease, Discount Rate	8.50%
Senhance Surgical Robotic System Acquisition[Member]
Business Combination, Contingent Consideration, Liability, Total	$ 4,200
Senhance Surgical Robotic System Acquisition[Member] | License and Supply Agreement [Member]
Contractual Obligation, to be Paid, Remainder of Fiscal Year			3,300
Contractual Obligation, to be Paid, Year One			500
Contractual Obligation, to be Paid, Year Two			500
Contractual Obligation, to be Paid, Year Three			500
Contractual Obligation, to be Paid, after Year Three			$ 500
Senhance Surgical Robotic System Acquisition[Member] | Minimum [Member]
Business Combination Contingent Consideration Arrangements Target Revenue | €		€ 25