Note 1 - Organization and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31, 2022		December 31, 2021
Cash	$	12,560	$	35,893
Cash equivalents		10,768		—
Restricted cash included in current assets		—		891
Restricted cash included in long-term assets		—		270
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	$	23,328	$	37,054

Debt Securities, Held-to-Maturity [Table Text Block]

Held-to-maturity debt securities:
Amortized cost	$	9,341
Gross unrecognized gains		—
Gross unrecognized losses		(168	)
Fair value	$	9,173

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Within one year	$	2,981	$	2,957
After one year through two years		4,919		4,807
After two years through three years		1,441		1,409
Total	$	9,341	$	9,173

Financing Receivable, Allowance for Credit Loss [Table Text Block]

Year	Balance at January 1		Provision charged to expense			Write-offs / Recoveries			Balance at December 31
2021	$	835	$	227		$	(839	)	$	223
2022	$	223	$	(19	)	$	(94	)	$	110

Schedule of Excess and Obsolete Inventory Reserve [Table Text Block]

Year	Balance at January 1		Provision charged to expense		Write-offs / Recoveries		Balance at December 31
2021	$	907	$	—	$	20	$	927
2022	$	927	$	—	$	—	$	927

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

	December 31,
	2022			2021
Foreign currency translation
Balance at beginning of period	$	(1,604	)	$	(1,370	)
Other comprehensive loss:
Foreign currency translation adjustments (1)		(124	)		(234	)
Balance at end of period	$	(1,728	)	$	(1,604	)
Total accumulated other comprehensive loss	$	(1,728	)	$	(1,604	)

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

			2022							2021
Description of Other Intangibles	Amortization Period (years)		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Patent assets		1 - 20		803		(406	)		397		789		(341	)		448
Total			$	803	$	(406	)	$	397	$	789	$	(341	)	$	448

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

Year	Estimated Amortization Expense
2023	$	60
2024		52
2025		31
2026		31
2027		31
Thereafter		192
Total	$	397

Property, Plant and Equipment [Table Text Block]

Description of Property and Equipment	Depreciable Life (years)		2022			2021
Land			$	1,050		$	1,050
Building		39		3,950			3,950
Building and leasehold improvements		3 - 39		2,626			2,626
Field equipment		3 - 4		11,882			11,787
Computer equipment and software		2 - 3		2,117			2,099
Furniture and fixtures		3 - 10		1,306			1,308
Vehicles		5		32			32
Construction in process				29			—
Total cost				22,992			22,852
Less accumulated depreciation				(18,557	)		(18,243	)
Total net book value			$	4,435		$	4,609

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	2022		2021
Basic weighted-average shares		30,289,000		29,585,000
Conversion of unsecured loan notes		—		—
Unexercised options and unvested restricted stock units		—		109,000
Diluted weighted-average shares		30,289,000		29,694,000