Note 3 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2023

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

			Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets		Other		Significant
	Balance at		for Identical		Observable		Unobservable
	June 30,		Items		Inputs		Inputs
	2023		(Level 1)		(Level 2)		(Level 3)
Assets
Restricted cash held as a certificate of deposit	$	324	$	324	$	—	$	—
Deposit held as a certificate of deposit		152		152		—		—
Total assets	$	476	$	476	$	—	$	—
Liabilities
Combined embedded derivative liability		169		—		169		—
Total liabilities	$	169	$	—	$	169	$	—

			Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets		Other		Significant
	Balance at		for Identical		Observable		Unobservable
	December 31,		Items		Inputs		Inputs
	2022		(Level 1)		(Level 2)		(Level 3)
Assets
Restricted cash held as a certificate of deposit	$	332	$	332	$	—	$	—
Deposit held as a certificate of deposit		152		152		—		—
Total assets	$	484	$	484	$	—	$	—