Note 6 - Prepaid Expenses and Other Current Assets - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Prepaid service invoices	$ 42	$ 79
Prepaid manufacturing and mold costs		91
Prepaid insurance premiums	198	193
Interest and other receivables	82
Total	$ 322	$ 363