Note 5 - Leases (Details Textual)		3 Months Ended		6 Months Ended
	Jul. 01, 2020 USD ($)	Jun. 30, 2020 USD ($) a ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) a ft²	Jun. 30, 2019 USD ($)
Operating Lease, Payments | $		$ 421,000	$ 577,000	$ 900,000	$ 1,100,000
HONG KONG
Area of Land (Acre) | a		9,600		9,600
HONG KONG | Subsequent Event [Member]
Percent of Increase in Monthly Lease Cost Savings	10.00%
Operating Lease Liability, Increase From Modification | $	$ 831,000
Rolling Hills Estates [Member]
Area of Land (Acre)		4,900		4,900
Lessee, Operating Lease, Renewal Term (Year)		5 years		5 years
Monterey Park, California [Member]
Area of Land (Acre)		2,400		2,400
Richmond, British Columbia [Member]
Area of Land (Acre)		1,600		1,600
Metuchen, New Jersey [Member]
Area of Land (Acre)		2,000		2,000
CHINA
Lessee, Number of Branches		8		8