Note 4 - Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Property, Plant and Equipment [Table Text Block]

	March 31,			December 31,
	2023			2022
Leasehold improvements	$	2,519		$	2,519
Laboratory equipment		1,149			1,118
Furniture, fixtures and equipment		966			966
Software		289			289
Construction in progress		30			22
		4,953			4,914
Less: Accumulated depreciation and amortization		(3,088	)		(2,953	)
	$	1,865		$	1,961

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	March 31,			December 31,
	2023			2022
Acquired patents and licenses	$	7,985		$	7,985
Less: Accumulated amortization		(5,601	)		(5,434	)
	$	2,384		$	2,551

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Years ending December 31:
2023 (remaining 9 months)	$	498
2024		665
2025		665
2026		556
	$	2,384

Schedule of Accrued Liabilities [Table Text Block]

	March 31,		December 31,
	2023		2022
Compensation expense	$	1,615	$	1,377
Director and officer liability insurance (Note 12)		815		571
Clinical trial fees and costs		49		64
Professional fees		351		318
Warranty		50		50
Other		211		215
	$	3,091	$	2,595