XML 56 R57.htm IDEA: XBRL DOCUMENT v3.20.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition, General and Administrative Expense and Foreign Currency Risk (Details)
$ in Thousands
 12 Months Ended
Jan. 01, 2018
USD ($)
item
Dec. 31, 2017
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
Dec. 31, 2019
USD ($)
Jan. 01, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Revenue recognition                    
Number of criteria to be met prior to recognition of revenue | item 4                  
Return period (in days)         14 days 30 days        
Accrued sales return             $ 381   $ 1,336 $ 1,236
Cost of goods sold     $ 146,029 $ 166,343 $ 214,261          
Allowance of doubtful accounts     $ 1,418 533            
VAT on sales as a percentage on revenue from the sale of products   17.00%                
Return period, subsequent to the receipt of shipment with quality-related issues     12 months              
Contract Balances                    
Advance from customers             21,731   17,732  
Contract liability $ 5,248 $ 5,248 $ 14,330 10,246 5,248   14,330   10,246 5,248
Accrued expenses and other current liabilities             28,642 $ 22,582 22,688  
Revenue included in advance from customers                    
Contract liability as of January 1, 2018 $ 5,248   10,246 5,248            
Cash received in advance, net of VAT     240,460 199,899            
Revenue recognized from opening balance of contract liability     (10,246) (5,248)            
Revenue recognized from contract liability arising during current year     (226,130) (189,653)            
Contract liability as of December 31, 2018   $ 5,248 $ 14,330 10,246 5,248          
Revenue, Remaining Performance Obligation, Optional Exemption, Performance Obligation [true false]     true              
Selling and marketing                    
Advertising expense     $ 41,975 43,308 62,767          
General and administrative                    
Research and development expense     17,871 5,694 5,207          
Chargeback incurred     1,836 2,938 2,929          
Income taxes                    
Income tax due to uncertain tax positions             0   0 $ 0
Accrued expenses and other current liabilities                    
Revenue recognition                    
Accrued sales return             381   1,336  
Product sales                    
Revenue recognition                    
Cost of goods sold     144,061 156,326 189,816          
Shipping and handling                    
Revenue recognition                    
Cost of goods sold     $ 36,691 $ 51,731 $ 60,131          
Foreign currency risk | Denominated in RMB                    
Foreign currency risk                    
Cash and cash equivalents, term deposit and restricted cash             $ 3,952   $ 4,368  
Maximum                    
Revenue recognition                    
Return period, subsequent to the receipt of shipment with no quality-related issues     7 days 14 days            
Return period, subsequent to the receipt of shipment with quality-related issues     30 days