ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accounts payable accruals	$ 36,732	$ 15,692
Accrued compensation and other related costs	25,305	13,012
Accrued marketing expenses	21,062	13,063
Allowance for returns	18,657	11,107	$ 15,261
Sales and other taxes payable	14,222	10,105
Accrued freight	11,706	5,954
Accrued loss contingencies	2,337	9,550
Other accrued expenses	14,089	9,714
Total accrued liabilities	$ 144,110	$ 88,197