Note 11 - Shareholders' Equity (Details Textual) - USD ($)		Mar. 08, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock Repurchase Program, Authorized Amount	[1]		$ 7,500,000	$ 7,500,000
Preferred Stock, Shares Authorized (in shares)			250,000
Preferred Stock, No Par Value (in dollars per share)			$ 0
Preferred Stock, Shares Issued, Total (in shares)			0
Preferred Stock, Shares Outstanding, Ending Balance (in shares)			0
Non-voting Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)			250,000
Preferred Stock, No Par Value (in dollars per share)			$ 0
Series A Non-voting Convertible Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)			125,000
Preferred Stock, Shares Issued, Total (in shares)			0	0
Preferred Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.06
Preferred Stock, Shares Outstanding, Ending Balance (in shares)			0	0
Subsequent Event [Member]
Stock Repurchase Program, Authorized Amount		$ 7,500,000

[1] Common shares can be purchased in the open market or privately negotiated transactions over the next twelve months from the date of plan authorization.