Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Accounts receivable, allowance for doubtful accounts	$ 0	$ 0
Inventory, allowance for excess and obsolete inventory and lower of cost or estimated net realizable value adjustments	$ 522	$ 641
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)	12,000	14,000
Preferred stock, shares issued (in shares)	12,000	14,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	100,000,000
Common stock, shares issued (in shares)	53,513,000	47,766,000
Common stock, shares outstanding (in shares)	53,513,000	47,766,000