Note 3 - Balance Sheet Detail - Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accumulated amortization and impairment amount	$ 4,663	$ 4,663
Goodwill, gross carrying amount	1,339	1,339
Goodwill	1,339	1,339
Total, gross carrying amount	6,002	6,002
Total	1,339	1,339
Patents [Member]
Gross carrying amount	1,218	1,218
Accumulated amortization and impairment amount	1,218	1,218
Net amount
Customer Relationships [Member]
Gross carrying amount	2,510	2,510
Accumulated amortization and impairment amount	2,510	2,510
Net amount
Other Intangible Assets [Member]
Gross carrying amount	780	780
Accumulated amortization and impairment amount	780	780
Net amount
Other Intangible [Member]
Gross carrying amount	155	155
Accumulated amortization and impairment amount	155	155
Net amount