Note 6 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Income Tax Expense (Benefit)	$ 90	$ 96
Deferred Tax Liabilities, Undistributed Foreign Earnings	0
Operating Loss Carryforwards	149,963	133,383
Deferred Tax Assets, Tax Credit Carryforwards, Research	5,489	5,403
Unrecognized Tax Benefits	10,460	3,053		$ 3,194
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(193)	96	$ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	193	(96)	$ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 1,373	$ 1,566
Foreign Tax Jurisdiction [Member] | Inland Revenue, Hong Kong [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent, Foreign	16.50%
Income Tax Expense (Benefit)	$ 0
Foreign Tax Jurisdiction [Member] | State Administration of Taxation, China [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent, Foreign	25.00%
Effective Income Tax Rate Reconciliation, at Preferential Income Tax Rate, Percent, Foreign	15.00%
Effective Income Tax Rate Reconciliation, at Preferential Income Tax Rate, Duration, Foreign (Year)	3 years
Operating Loss Carryforwards	$ 21,654
Domestic Tax Jurisdiction [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards	$ 128,309				$ 18,347
Operating Loss Carryforwards, Term		20 years