Note 2 - Investments and Fair Value Measurement - Fair Value of Financial Assets and Liabilities by Level Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Assets, fair value	$ 16,721	$ 19,967
Liabilities, fair value	1,713	2,376
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	387	2,521
Liabilities, fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Assets, fair value	16,334	17,446
Liabilities, fair value	0	0
Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
Liabilities, fair value	1,713	2,376
Money Market Funds [Member]
Assets, fair value	387	2,521
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Assets, fair value	387	2,521
Money Market Funds [Member] \| Fair Value, Inputs, Level 2 [Member]
Assets, fair value	0	0
Money Market Funds [Member] \| Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
US Government Agencies Debt Securities [Member]
Assets, fair value	16,334	17,446
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Assets, fair value	0	0
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Assets, fair value	16,334	17,446
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
Warrant Liability [Member]
Liabilities, fair value	1,713	2,376
Warrant Liability [Member] \| Fair Value, Inputs, Level 1 [Member]
Liabilities, fair value	0	0
Warrant Liability [Member] \| Fair Value, Inputs, Level 2 [Member]
Liabilities, fair value	0	0
Warrant Liability [Member] \| Fair Value, Inputs, Level 3 [Member]
Liabilities, fair value	$ 1,713	$ 2,376