Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts receivable, allowance for doubtful accounts	$ 24	$ 10
Inventory, allowance for excess and obsolete inventory and lower of cost or estimated net realizable value adjustments	$ 135	$ 104
Temporary equity, par value (in dollars per share)	$ 0.01	$ 0.01
Temporary equity, shares authorized (in shares)	2,700	2,700
Temporary equity, shares issued (in shares)	2,700	0
Temporary equity, shares outstanding (in shares)	2,700	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	50,000	240,000
Common stock, shares issued (in shares)	25,202	17,089
Common stock, shares outstanding (in shares)	25,202	17,089