Note 2 - Summary of Significant Accounting Policies (Details Textual)		3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 18, 2019	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.0001			$ 0.0001		$ 0.0001	[1]
Common Stock, Shares Authorized (in shares) | shares		75,000,000			75,000,000		75,000,000	[1]
Number of Financial Institutions		1			1
Accounts Receivable, Allowance for Credit Loss, Ending Balance		$ 566,000			$ 566,000		$ 407,000
Accounts Receivable, Allowance for Credit Loss, Writeoff		0	$ 0		173,000	$ 0
Revenue from Contract with Customer, Excluding Assessed Tax, Total		1,524,000	1,052,000		3,532,000	5,116,000
Deferred Income		617,000			617,000		662,000
Contract with Customer, Asset, after Allowance for Credit Loss, Total		0			0		0
Contract with Customer, Liability, Total							108,000
Capitalized Contract Cost, Net, Total		55,000			55,000		$ 337,000
Capitalized Contract Cost, Amortization		58,000	30,000		538,000	30,000
Capitalized Contract Cost, Impairment Loss					0
Equity Method Investment, Other than Temporary Impairment		$ 0	0	$ 0	$ 0
Series B Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares) | shares		34,735			34,735		31,678	[1]
Convertible Preferred Stock, Shares Issued upon Conversion (in shares) | shares		22,702,614			22,702,614
Conversion of Stock Exchange Ratio					653.59
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares		$ 1,000			$ 1,000
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares		$ 1.53			$ 1.53
Minimum [Member]
Warranty Period (Year)					1 year
Maximum [Member]
Warranty Period (Year)					3 years
Rental [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		$ 471,000	$ 177,000		$ 829,000	$ 177,000
Rental Program Equipment [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		197,000			499,000
Marketing Programs [Member]
Contract with Customer, Liability, Total		0			0		$ 108,000
Contract with Customer, Liability, Revenue Recognized		$ 21,000			$ 108,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Number of Customers		1	2		1	1
Concentration Risk, Percentage		40.00%	31.00%		45.00%	17.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Concentration Risk, Number of Customers					1		2
Concentration Risk, Percentage					16.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Two Customers [Member]
Concentration Risk, Percentage							49.00%
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	100

[1] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.