Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2019
Summary of Significant Accounting Policies [Abstract]  
Inventories Inventories consist of the following (U.S. dollars in thousands):


 
December 31,
  
   
2019
    
2018
  
Raw materials
  
$
87,942
    
$
91,610
  
Finished goods
    
187,949
      
204,211
  
Total inventory, net
  
$
275,891
    
$
295,821
  
Inventory Reserves Reserves of inventories consist of the following (U.S. dollars in thousands):


 
2019
    
2018
    
2017
  
Beginning balance
  
$
14,149
    
$
8,081
    
$
7,995
  
Additions
    
14,931
      
23,940
      
16,382
  
Write-offs
    
(16,785
)
    
(17,872
)
    
(16,296
)
Ending balance
  
$
12,295
    
$
14,149
    
$
8,081
  
Prepaid Expenses and Other Prepaid expenses and other consist of the following (U.S. dollars in thousands):


 
December 31,
  
   
2019
    
2018
  
Deferred charges
  
$
8,142
    
$
6,703
  
Prepaid income tax
    
8,905
      
—
  
Prepaid inventory and import costs
    
4,277
      
2,808
  
Prepaid rent, insurance and other occupancy costs
    
12,516
      
8,799
  
Prepaid promotion and event cost
    
7,159
      
6,013
  
Prepaid other taxes
    
7,965
      
6,268
  
Prepaid software license
    
3,317
      
4,006
  
Deposits
    
1,208
      
1,470
  
Other
    
16,365
      
15,810
  
 Total prepaid expenses and other
  
$
69,854
    
$
51,877
  
Estimated Useful Lives Depreciation is recorded using the straight-line method over the following estimated useful lives:

Buildings
39 years
Furniture and fixtures
5 - 7 years
Computers and equipment
3 - 5 years
Leasehold improvements
Shorter of estimated useful life or lease term
Scanners
3 years
Vehicles
3 - 5 years
Other Assets Other assets consist of the following (U.S. dollars in thousands):


 
December 31,
  
   
2019
    
2018
  
Deferred taxes
  
$
30,780
    
$
37,332
  
Deposits for noncancelable operating leases
    
46,894
      
41,986
  
Cash surrender value for life insurance policies
    
41,707
      
35,590
  
Other
    
34,635
      
29,204
  
 Total other assets
  
$
154,016
    
$
144,112
  
Accrued Expenses Accrued expenses consist of the following (U.S. dollars in thousands):


 
December 31,
  
   
2019
    
2018
  
Accrued sales force commissions and other payments
  
$
103,532
    
$
128,022
  
Accrued income taxes
    
—
      
6,674
  
Accrued other taxes
    
29,657
      
38,693
  
Accrued payroll and other employee expenses
    
30,610
      
68,155
  
Accrued payable to vendors
    
34,760
      
34,539
  
Short-term lease liability
    
39,349
      
—
  
Accrued royalties
    
514
      
3,899
  
Sales return reserve
    
3,903
      
3,577
  
Deferred revenue
    
20,162
      
20,104
  
Other
    
27,794
      
18,920
  
 Total accrued expenses
  
$
290,281
    
$
322,583
  
Other Liabilities Other liabilities consist of the following (U.S. dollars in thousands):


 
December 31,
  
   
2019
    
2018
  
Deferred tax liabilities
  
$
10,741
    
$
18,236
  
Reserve for other tax liabilities
    
17,121
      
14,382
  
Liability for deferred compensation plan
    
43,238
      
36,398
  
Pension plan benefits reserve
    
3,454
      
3,023
  
Build to suit – financing obligation
    
—
      
9,332
  
Deferred rent and deferred tenant incentives
    
—
      
5,665
  
Asset retirement obligation
    
6,631
      
6,444
  
Other
    
15,610
      
18,436
  
Total other liabilities
  
$
96,795
    
$
111,916
  
Reconciliation of Unrecognized Tax Benefits A reconciliation of the beginning and ending amount of unrecognized tax benefits included in other liabilities is as follows (U.S. dollars in thousands):


 
2019
    
2018
    
2017
  
Gross balance at January 1
  
$
11,456
    
$
5,514
    
$
5,290
  
Increases related to prior year tax positions
    
775
      
5,161
      
—
  
Decreases related to prior year tax positions
    
—
      
—
      
(277
)
Increases related to current year tax positions
    
2,273
      
3,704
      
669
  
Settlements
    
—
      
(956
)
    
(159
)
Decreases due to lapse of statutes of limitations
    
(1,051
)
    
(1,483
)
    
(187
)
Currency adjustments
    
54
      
(484
)
    
178
  
Gross balance at December 31
  
$
13,507
    
$
11,456
    
$
5,514