Condensed Consolidated Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 53,000	$ 64,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	[1]
Common stock, shares authorized (in shares)	50,000,000	50,000,000	[1]
Common stock, shares outstanding (in shares)	12,885,273	13,502,684	[1]

[1] The condensed consolidated balance sheet as of December 31, 2018 has been prepared using information from the audited consolidated balance sheet as of that date.