Concentrations and Risks (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues earned in geographic areas
Revenues	$ 448,508	$ 415,581
Wholesale Business [Member]
Revenues earned in geographic areas
Revenues	218,609	190,236
Retail Business [Member]
Revenues earned in geographic areas
Revenues	229,899	225,345
Mainland China [Member]
Revenues earned in geographic areas
Revenues	89,269	65,811
Hong Kong China [Member]
Revenues earned in geographic areas
Revenues	38,106	39,738
Germany [Member]
Revenues earned in geographic areas
Revenues	6,748	8,901
United Kingdom
Revenues earned in geographic areas
Revenues	15,460	12,417
Europe Other [Member]
Revenues earned in geographic areas
Revenues	30,747	34,804
Japan [Member]
Revenues earned in geographic areas
Revenues	7,583	3,515
United States [Member]
Revenues earned in geographic areas
Revenues	$ 30,696	$ 25,050