Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Trade accounts receivable, less allowances	$ 14	$ 8
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	2,597,470	2,597,470
Preferred stock, outstanding (in shares)	2,597,470	2,597,470
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	50,000,000	50,000,000
Common stock, issued (in shares)	3,682,816	3,525,374
Common stock, outstanding (in shares)	3,682,816	3,525,374
Series A Convertible Preferred Stock
Preferred stock, authorized (in shares)	3,300,000	3,300,000