Note 1 - Organization and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31, 2023		December 31, 2022
Cash	$	12,495	$	12,560
Cash equivalents		5,083		10,768
Total cash and cash equivalents shown in the Consolidated Statements of Cash Flows	$	17,578	$	23,328

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

	December 31,
	2023			2022
Held-to-maturity debt securities:
Amortized cost	$	15,800		$	9,341
Gross unrecognized gains		—			—
Gross unrecognized losses		(86	)		(168	)
Fair value	$	15,714		$	9,173

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Within one year	$	12,136	$	12,056
After one year through two years		3,664		3,658
Total	$	15,800	$	15,714

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
2022	$	223	$	(19	)	$	(94	)	$	110
2023	$	110	$	24		$	(23	)	$	111

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
2022	$	927	$	—		$	—		$	927
2023	$	927	$	(56	)	$	(258	)	$	613

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

	December 31,
	2023			2022
Foreign currency translation
Balance at beginning of period	$	(1,728	)	$	(1,604	)
Other comprehensive loss:
Foreign currency translation adjustments (1)		(20	)		(124	)
Balance at end of period	$	(1,748	)	$	(1,728	)
Total accumulated other comprehensive loss	$	(1,748	)	$	(1,728	)

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

			2023							2022
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		826		(468	)		358		803		(406	)		397
Total			$	826	$	(468	)	$	358	$	803	$	(406	)	$	397

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

Year	Estimated Amortization Expense
2024	$	54
2025		33
2026		32
2027		32
2028		32
Thereafter		175
Total	$	358

Property, Plant and Equipment [Table Text Block]

Description of Property and Equipment	Depreciable Life (years)		2023			2022
Land			$	1,050		$	1,050
Building		39		3,950			3,950
Building and leasehold improvements		3 - 39		2,655			2,626
Field equipment		3 - 4		12,100			11,882
Computer equipment and software		2 - 3		2,049			2,117
Furniture and fixtures		3 - 10		1,307			1,306
Vehicles		5		32			32
Construction in process				99			29
Total cost				23,242			22,992
Less accumulated depreciation				(18,703	)		(18,557	)
Total net book value			$	4,539		$	4,435

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

	2023		2022
Basic weighted-average shares		30,348,000		30,289,000
Conversion of unsecured loan notes		—		—
Unexercised options and unvested restricted stock units		—		—
Diluted weighted-average shares		30,348,000		30,289,000