INCOME TAXES - Deferred tax (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Accruals and advances	$ 7,174	$ 8,586
Stock-based compensation	4,277	3,750
Accruals for chargebacks and returns	13,831	7,603
Inventory	6,101	4,720
Intangible asset	21,911	14,923
Net operating loss carryforwards	4,090	4,767
Other	2,171	1,459
Total deferred tax assets	59,555	45,808
Deferred tax liabilities:
Depreciation	(5,913)	(6,029)
Intangible assets	(11)	(13)
Other	(1,664)	(1,008)
Total deferred tax liabilities	(7,588)	(7,050)
Valuation allowance	(263)	(432)
Deferred tax assets, net of deferred tax liabilities and valuation allowance	$ 51,704	$ 38,326