Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, allowance for doubtful accounts	$ 3,148	$ 3,393
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	19,629,403	16,382,543
Common stock, shares outstanding (in shares)	19,629,403	16,382,543