Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Letters of Credit Outstanding, Amount	$ 500	$ 500
Restricted Cash and Cash Equivalents, Current, Total	3,212	3,212	$ 309
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 343	$ 343	$ 335
Preferred Stock, Dividend Rate, Percentage		12.00%
Preferred Stock, Liquidation Preference Per Share (in dollars per share)	$ 1	$ 1
Preferred Stock, Dividends Per Share, Declared (in dollars per share)		$ 0	$ 0
Advertising Expense		$ 42	$ 101
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)		0	0
Cumulative Translation Adjustment, Net of Tax, Period Increase (Decrease), Total	$ (220)
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance	$ 37	$ 37	$ 257
Foreign Currency Transaction Gain (Loss), before Tax, Total		$ 32	$ 11
Revenue Benchmark [Member] | Product Concentration Risk [Member]
Concentration Risk, Percentage		2.10%	3.10%