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STOCK-BASED AWARDS - Stock-based Compensation Expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 2,465,000	$ 5,171,000	$ 5,733,000	$ 9,156,000
Medici Ventures \| Employee Stock Options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			13,650
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	282,000		$ 282,000
tZero.com, Inc. \| Restricted Stock Awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			60,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	46,000		$ 46,000
Cost of Sales [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	49,000	54,000	103,000	101,000
Selling and Marketing Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	309,000	533,000	697,000	974,000
Technology [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	447,000	1,670,000	1,362,000	2,897,000
General and Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 1,660,000	$ 2,914,000	$ 3,571,000	$ 5,184,000