Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ / shares in Thousands, $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts receivable, allowance for doubtful accounts	$ 50	$ 50
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	37,500,000	37,500,000
Common stock, shares issued (in shares)	20,445,880	20,374,406
Common stock, shares outstanding (in shares)	20,445,880	20,374,406