Concentrations and Risks (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues earned in geographic areas
Revenues	$ 77,316	$ 88,541	$ 165,272	$ 181,326
Wholesale Business [Member]
Revenues earned in geographic areas
Revenues	37,251	38,814	65,353	64,070
Retail Business [Member]
Revenues earned in geographic areas
Revenues	40,065	49,727	99,919	117,256
The People’s Republic of China [Member]
Revenues earned in geographic areas
Revenues	6,491	9,131	17,246	13,342
Hong Kong China [Member]
Revenues earned in geographic areas
Revenues	6,463	7,418	7,717	12,556
Germany [Member]
Revenues earned in geographic areas
Revenues	877	899	1,726	2,765
United Kingdom
Revenues earned in geographic areas
Revenues	2,038	2,881	2,838	5,099
Europe-Other [Member]
Revenues earned in geographic areas
Revenues	4,224	5,833	9,453	10,285
Japan [Member]
Revenues earned in geographic areas
Revenues	1,311	1,881	6,248	4,318
United States [Member]
Revenues earned in geographic areas
Revenues	$ 15,847	$ 10,771	$ 20,125	$ 15,705