Note 11 - Segment Information - Consolidated Net Sales by Region (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Net sales	$ 26,650,000	$ 25,679,000	$ 51,567,000	$ 52,242,000
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member]
Net sales	$ 26,700,000	$ 25,700,000	$ 51.6	$ 52.2
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| UNITED STATES
Net sales	$ 6,500,000	$ 5,800,000	$ 11.1	$ 12.2
Concentration Risk, Percentage	24.30%	22.60%	21.50%	23.40%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| Americas, Other [Member]
Net sales	$ 1,900,000	$ 2,500,000	$ 4	$ 5
Concentration Risk, Percentage	7.10%	9.70%	7.80%	9.60%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| Americas [Member]
Net sales	$ 8,400,000	$ 8,300,000	$ 15.1	$ 17.2
Concentration Risk, Percentage	31.50%	32.30%	29.30%	33.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| CHINA
Net sales	$ 3,600,000	$ 3,000,000	$ 6.2	$ 0
Concentration Risk, Percentage	13.50%	11.70%	12.00%	0.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| KOREA, REPUBLIC OF
Net sales	$ 9,600,000	$ 9,500,000	$ 19.8	$ 20
Concentration Risk, Percentage	36.00%	37.00%	38.40%	38.30%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| Asia Pacific, Other [Member]
Net sales	$ 2,700,000	$ 2,800,000	$ 5.7	$ 10.7
Concentration Risk, Percentage	10.10%	10.90%	11.00%	20.50%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| Asia Pacific [Member]
Net sales	$ 15,900,000	$ 15,300,000	$ 31.7	$ 30.7
Concentration Risk, Percentage	59.60%	59.50%	61.40%	58.80%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| EMEA [Member]
Net sales	$ 2,400,000	$ 2,100,000	$ 4.8	$ 4.3
Concentration Risk, Percentage	9.00%	8.20%	9.30%	8.20%