Note 13 - Customer and Geographic Information - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 85,585	$ 85,794
Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Revenues	$ 85,585	$ 85,794
Percentage of Revenues	100.00%	100.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Revenues	$ 36,169	$ 34,179
Percentage of Revenues	42.00%	40.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | CHINA
Revenues	$ 13,960	$ 17,465
Percentage of Revenues	16.00%	20.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | TAIWAN, PROVINCE OF CHINA
Revenues	$ 8,574	$ 7,890
Percentage of Revenues	10.00%	9.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | JAPAN
Revenues	$ 5,829	$ 5,240
Percentage of Revenues	7.00%	6.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | Rest of the World [Member]
Revenues	$ 21,053	$ 21,020
Percentage of Revenues	25.00%	25.00%