Note 17 - Segment Information - Summary of Operations Within Geographic Areas Based on Customer Locations (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 117,613	$ 117,438	$ 124,753
UNITED STATES
Revenues	4,947	5,876	4,927
HONG KONG
Revenues	31,692	36,666	46,119
JAPAN
Revenues	11,249	14,284	16,567
Europe [Member]
Revenues	9,546	9,022	9,882
CHINA
Revenues	22,813	16,107	16,096
TAIWAN, PROVINCE OF CHINA
Revenues	26,634	23,940	22,442
KOREA, REPUBLIC OF
Revenues	7,285	7,341	4,190
Other Geographic Regions [Member]
Revenues	$ 3,447	$ 4,202	$ 4,530

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Name:	us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration