Note 4 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

			Fair Value Measurements Using
	Balance at		Quoted Prices in		Significant		Significant
	March 31,		Active Markets		Other		Unobservable
	2022		for Identical		Observable		Inputs
			Items		Inputs		(Level 3)
			(Level 1)		(Level 2)
Assets
Deposit held as a certificate of deposit		152		152		—		—
Total assets	$	152	$	152	$	—	$	—
Liabilities
Warrant liability	$	—		—		—	$	—
Contingent earnout liability		342		—		—		342
Total liabilities	$	342	$	—	$	—	$	342

			Fair Value Measurements Using
	Balance at		Quoted Prices in		Significant		Significant
	December 31,		Active Markets		Other		Unobservable
	2021		for Identical		Observable		Inputs
			Items		Inputs		(Level 3)
			(Level 1)		(Level 2)
Assets
Restricted cash held as a certificate of deposit	$	324	$	324	$	—	$	—
Deposit held as a certificate of deposit		151		151		—		—
Total assets	$	475	$	475	$	—	$	—
Liabilities
Warrant liability	$	9,558		—		—	$	9,558
Contingent earnout liability		561		—		—		561
Total liabilities	$	10,119	$	—	$	—	$	10,119

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

Fair value of warrant liability at December 31, 2021	$	9,558
Decrease in fair value of 2021 Warrants		(2,056	)
Reclassification of warrant liability to equity		(7,502	)
Fair value of warrant liability at March 31, 2022	$	—
Fair value of contingent liability at December 31, 2021	$	561
Decrease in fair value of contingent liability		(219	)
Fair value of contingent liability at March 31, 2022	$	342

Fair value of warrant liability at December 31, 2020	$	—
Fair value of 2021 Warrants issued		14,172
Decrease in fair value of 2021 Warrants		(4,614	)
Fair value of warrant liability at December 31, 2021	$	9,558