STOCK-BASED AWARDS - Summary of Stock Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 2,075	$ 3,386	$ 3,608	$ 4,480
Income Statement Location [Axis]: byon:CustomerServiceAndMerchantFees
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	2	0	3	0
Income Statement Location [Axis]: byon:TechnologyExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	27	662	381	719
Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	0	1	0	2
Income Statement Location [Axis]: us-gaap:GeneralAndAdministrativeExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	2,249	2,681	3,357	3,614
Income Statement Location [Axis]: us-gaap:SellingAndMarketingExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ (203)	$ 42	$ (133)	$ 145