Accrued Expenses And Other Liabilities (Schedule Of Accrued Expenses & Other Current Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued compensation and benefits	$ 31,010	$ 20,898
Fulfillment, freight and duties	11,784	14,572
Professional services	11,578	10,900
Sales/use and value added taxes payable	5,027	4,978
Accrued rent and occupancy	6,551	7,335
Royalties payable and deferred revenue	6,758	7,475
Other	12,128	12,124
Total accrued expenses and other liabilities	$ 84,836	$ 78,282