Note 4 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	Convertible Preferred Stock Warrant Liability			Total
	(in thousands)
Balance at January 1, 2018	$	67		$	67
Issuances		—			—
Revaluation loss included in loss on revaluation of financial instruments		3			3
Settlements		(70	)		(70	)
Balance at December 31, 2018	$	—		$	—
Total losses included in other income and (expenses) attributable to liabilities still held as of December 31, 2018	$	—		$	—