ACCOUNTING POLICIES - Additional Information (Details)					12 Months Ended
	Sep. 21, 2018 USD ($) shares	Jan. 17, 2018 USD ($) shares	Dec. 29, 2017 USD ($) shares	Nov. 08, 2017 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) bank subsidiary $ / shares	Dec. 31, 2018 USD ($) bank $ / shares	Dec. 31, 2018 USD ($) bank $ / shares	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Jan. 01, 2018 USD ($)
Accounting Policies [Abstract]
Cash equivalents					$ 2,800,000	$ 3,100,000	$ 3,100,000
Normal credit term granted to customers					30 days
Allowance for doubtful accounts receivable					$ 2,500,000	$ 2,100,000	$ 2,100,000
Number of banks who hold majority of cash and cash equivalents | bank					1	1	1
Accounting Policies [Line Items]
Marketable Securities and Equity Securities, FV-NI					$ 11,100,000	$ 2,600,000	$ 2,600,000
Operating Lease, Liability					$ 28,157,000
Preferred Stock, Par or Stated Value Per Share | $ / shares					$ 0.0001	$ 0.0001	$ 0.0001
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount					$ 24,200,000	$ 25,900,000	$ 25,900,000
Temporary Equity, Liquidation Preference Per Share | $ / shares					$ 0.10
Withdrawal Under Security Token Offering							22,000,000
Goodwill, Impairment Loss					$ 0	0
Advertising expense					$ 124,300,000	249,700,000		164,600,000
Sales return period for which full refund will be granted					30 days
Net other comprehensive income					$ 16,000	15,000		941,000
Other current assets					3,088,000	2,963,000	2,963,000
Impairment Of Cryptocurrencies					334,000	10,463,000		0
Impairments of long-lived assets					1,400,000	6,000,000		0
Impairments on intangible assets					1,406,000	$ 6,000,000		0
Indefinite-Lived Intangible Asset, Useful Life						0 years
Gain on sale of cryptocurrencies					569,000	$ 8,400,000		0
Goodwill, Acquired During Period					1,685,000	8,197,000
Equity Securities, FV-NI					823,000	2,636,000	2,636,000
Carrying value of equity method investments					$ 37,300,000	40,100,000	40,100,000
Number of broker-dealer subsidiary (in subsidiary) | subsidiary					2
Capitalized Offering Costs for Security Token Offering						(21,500,000)	(21,500,000)
Number of warrants called | shares		1,250,000	2,472,188	3,722,188
Proceeds from Issuance of Warrants				$ 6,500,000	$ 0	50,588,000		106,462,000
Warrant price (in usd per share) | $ / shares				$ 40.45
Proceeds from exercise of stock warrants		$ 50,600,000	$ 100,000,000
Loyalty program expiration period					90 days
Gift card and Club-O rewards breakage					$ 0	0		$ 2,742,000
Cumulative effect of new accounting pronouncement in period of adoption, reduction in accumulated deficit					(580,390,000)	(458,897,000)	(458,897,000)
Deferred revenue					$ 41,821,000	$ 50,578,000	50,578,000
Advertising Revenue as a Percentage of Total Revenue					2.00%	2.00%		2.00%
Maximum revenue from co-branded credit card program as a percentage of total net revenues						1.00%		1.00%
Sales return period for which reduced refund will be granted					30 days
Sales return received at returns processing facility for which reduced refund will be granted, period					45 days
Prepaid advertising					$ 138,000	$ 961,000	961,000
Amortization of intangible assets, 2019					3,700,000
Amortization of intangible assets, 2020					3,300,000
Amortization of intangible assets, 2021					2,100,000
Amortization of intangible assets, 2022					1,600,000
Amortization of intangible assets, 2023					804,000
Amortization of intangibles, thereafter					$ 323,000
Product delivery period from date of shipment, minimum					1 day
Product delivery period from date of shipment, maximum					8 days
Operating lease right-of-use assets					$ 25,384,000	0	0
Cryptocurrency, bitcoin
Accounting Policies [Line Items]
Other current assets					2,600,000	2,393,000	2,393,000
Software Development
Accounting Policies [Line Items]
Capitalized costs					13,000,000	19,300,000		$ 9,600,000
Amortization of capitalized costs					12,900,000	13,800,000		15,900,000
Medici Land Governance
Accounting Policies [Line Items]
Equity method investment, shares acquired (in shares) | shares	510,000
Proceeds from Noncontrolling Interests	$ 6,700,000
Patrick Byrne
Accounting Policies [Line Items]
Equity method investment, shares acquired (in shares) | shares	390,000
Patrick Byrne | Medici Land Governance
Accounting Policies [Line Items]
Sale of Stock, Percentage of Ownership after Transaction	43.00%
Medici Ventures [Member] | Medici Land Governance
Accounting Policies [Line Items]
Sale of Stock, Percentage of Ownership after Transaction	57.00%
Accumulated other comprehensive loss
Accounting Policies [Line Items]
Net other comprehensive income					16,000	15,000		$ 941,000
Accounting Standards Update 2014-09
Accounting Policies [Line Items]
Cumulative effect of new accounting pronouncement in period of adoption, reduction in accumulated deficit										$ 5,000,000
Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
Operating Lease, Liability									$ 35,100,000
Operating lease right-of-use assets									31,000,000
Operating Lease, Deferred Rent Offset To Right-Of-Use Asset									$ 4,200,000
Club O Reward Points [Member]
Accounting Policies [Line Items]
Deferred revenue					6,700,000	6,900,000	$ 6,900,000
Retail
Accounting Policies [Line Items]
Gift card and Club-O rewards breakage					$ 4,200,000	$ 5,600,000
Series A-1, issued and outstanding - 4,210 and 0 (including 4,085 shares declared as a stock dividend, not yet distributed)
Accounting Policies [Line Items]
Preferred Stock, Par or Stated Value Per Share | $ / shares					$ 0.0001
Series B, issued and outstanding - 357 and 355
Accounting Policies [Line Items]
Preferred Stock, Par or Stated Value Per Share | $ / shares					0.0001	$ 0.0001	$ 0.0001
Series A, issued and outstanding - 0 and 127
Accounting Policies [Line Items]
Preferred Stock, Par or Stated Value Per Share | $ / shares					$ 0.0001	$ 0.0001	$ 0.0001