Note 2 - Fair Value of Financial Instruments - Summary of Fair Value Hierarchy for Financial Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets, fair value	$ 47,417
Fair Value, Recurring [Member]
Assets, fair value	47,417	$ 23,088
Fair Value, Recurring [Member] | Money Market Securities [Member]
Assets, fair value	5,081	1,515
Fair Value, Recurring [Member] | Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets, fair value	22,222	14,622
Fair Value, Recurring [Member] | US Treasury Securities [Member]
Assets, fair value	14,362	5,953
Fair Value, Recurring [Member] | Federal Agency Notes [Member]
Assets, fair value	5,752	998
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	5,081	1,515
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Securities [Member]
Assets, fair value	5,081	1,515
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Federal Agency Notes [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	42,336	21,573
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Securities [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets, fair value	22,222	14,622
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Assets, fair value	14,362	5,953
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Federal Agency Notes [Member]
Assets, fair value	5,752	998
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Securities [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Assets, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Federal Agency Notes [Member]
Assets, fair value	$ 0	$ 0