Note 2 - Summary of Significant Accounting Policies 1 (Details Textual) $ in Thousands				1 Months Ended	2 Months Ended	3 Months Ended		12 Months Ended
	Jan. 29, 2021 USD ($)	Jan. 12, 2021 USD ($)	Dec. 11, 2019 shares	Jan. 31, 2021 USD ($)	Mar. 11, 2021 USD ($)	Dec. 31, 2019 USD ($) shares	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 10, 2019 shares	Dec. 31, 2018 USD ($)	Sep. 23, 2018 USD ($)	Sep. 21, 2015 USD ($)	Sep. 03, 2013 USD ($)
Common Stock, Shares, Outstanding, Ending Balance (in shares) | shares			20,200,000			20,691,301		116,231,072	20,691,301	261,900,000
Retained Earnings (Accumulated Deficit), Ending Balance						$ (663,600)		$ (722,912)	$ (663,600)
Working Capital								23,700
Cash and Cash Equivalents, at Carrying Value, Ending Balance						9,598		16,363	9,598
Proceeds from Warrant Exercises								3,340	538
Restricted Cash and Cash Equivalents, Noncurrent, Total						969		1,166	969
Accounts Receivable, Credit Loss Expense (Reversal)								0	1,634
Accounts Receivable, Allowance for Credit Loss, Ending Balance						1,654		1,802	1,654
Impairment of Intangible Assets, Finite-lived								0	7,912
Finite-Lived Intangible Assets, Net, Ending Balance						28,596		22,267	28,596
Goodwill, Ending Balance						0			0		$ 80,131
Goodwill, Impairment Loss						79,000	$ 79,000	$ 0	78,969
Period Of Service Sale Arrangement (Year)								5 years
Period of Service Sale Arrangement at Stated Service Price (Year)								4 years
Operating Lease, Lease Income, Total								$ 700	0
Revenue, Remaining Performance Obligation, Amount						3,700		3,100	3,700
Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total						200		100	200
Contract with Customer, Liability, Revenue Recognized								600	1,000
Inventory Write-down								0	8,931
Share-based Payment Arrangement, Expense								$ 7,900	11,500
Number of Operating Segments								1
Assets, Total						74,779		$ 78,258	74,779
Non-US [Member]
Assets, Total						60,500		56,800	60,500
System Sold in 2017 [Member]
Contract with Customer, Liability, Revenue Recognized									1,300
Systems [Member]
Inventory Write-down								$ 0	1,500
Safe Stitch Medical Inc [Member]
Goodwill, Ending Balance														$ 93,800
Senhance Surgical Robotic System Acquisition [Member]
Goodwill, Ending Balance													$ 38,300
Medical Surgery Technologies Limited [Member]
Goodwill, Ending Balance												$ 9,600
Patents [Member]
Finite-Lived Intangible Asset, Useful Life (Year)								10 years
Developed Technology Rights [Member]
Finite-Lived Intangible Assets, Net, Ending Balance						28,287		$ 21,976	28,287
Developed Technology Rights [Member] | Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)								5 years
Developed Technology Rights [Member] | Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)								7 years
Intellectual Property [Member]
Impairment of Intangible Assets, Finite-lived								$ 0	0
Finite-Lived Intangible Assets, Net, Ending Balance						28,596		22,267	28,596
In Process Research and Development [Member]
Impairment of Intangible Assets, Finite-lived						0	$ 7,900	0	(7,912)
Finite-Lived Intangible Assets, Net, Ending Balance						$ 2,470		$ 0	$ 2,470		$ 10,747
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Seven Customers [Member]
Number of Major Customers								7
Concentration Risk, Percentage								68.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Eight Customers [Member]
Number of Major Customers									8
Concentration Risk, Percentage									85.00%
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Nine Customers [Member]
Number of Major Customers								9
Concentration Risk, Percentage								55.00%
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Six Customers [Member]
Number of Major Customers									6
Concentration Risk, Percentage									82.00%
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | UNITED STATES
Concentration Risk, Percentage								27.00%	6.00%
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Europe [Member]
Concentration Risk, Percentage								53.00%	39.00%
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Asia [Member]
Concentration Risk, Percentage								20.00%	55.00%
Assets, Total [Member] | Geographic Concentration Risk [Member] | UNITED STATES
Concentration Risk, Percentage								27.00%	19.00%
Assets, Total [Member] | Geographic Concentration Risk [Member] | Non-US [Member]
Concentration Risk, Percentage								73.00%	81.00%
Long-lived Assets [Member] | Geographic Concentration Risk [Member] | UNITED STATES
Concentration Risk, Percentage								11.00%	8.00%
Long-lived Assets [Member] | Geographic Concentration Risk [Member] | ITALY
Concentration Risk, Percentage								48.00%	63.00%
Long-lived Assets [Member] | Geographic Concentration Risk [Member] | SWITZERLAND
Concentration Risk, Percentage								41.00%	27.00%
Subsequent Event [Member]
Proceeds from Warrant Exercises					$ 30,400
Subsequent Event [Member] | Public Offering [Member]
Proceeds from Issuance of Common Stock	$ 73,500			$ 73,500
Subsequent Event [Member] | Registered Direct Offering [Member]
Proceeds from Issuance of Common Stock		$ 28,800		28,800
Subsequent Event [Member] | ATM Offering [Member]
Proceeds from Issuance of Common Stock				$ 28,100
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio			13