Accrued Expenses And Other Liabilities (Schedule Of Accrued Expenses & Other Current Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued compensation and benefits	$ 30,461	$ 43,970
Fulfillment, freight, and duties	14,610	12,234
Professional services	15,537	11,124
Accrued rent and occupancy	5,047	6,956
Return liabilities	10,977	6,429
Sales/use and value added taxes payable	11,197	5,601
Royalties payable and deferred revenue	2,953	3,356
Other	9,160	12,501
Total accrued expenses and other liabilities	$ 99,942	102,171
Accrued inducements		$ 3,000