Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, allowance for doubtful accounts	$ 407	$ 284
Convertible preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	7,075,684	463,630
Common stock, shares outstanding (in shares)	7,075,684	463,630
Series A Preferred Stock [Member]
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares issued (in shares)	1,852,173	0
Convertible preferred stock, shares outstanding (in shares)	1,852,173	0
Series B Preferred Stock [Member]
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares issued (in shares)	31,678	0
Convertible preferred stock, shares outstanding (in shares)	31,678	0