STOCKHOLDERS' EQUITY (Details)							1 Months Ended	12 Months Ended
	Jun. 26, 2019 shares	May 08, 2019 USD ($) shares	May 06, 2019 USD ($) $ / shares	Jan. 17, 2018 USD ($) shares	Dec. 29, 2017 USD ($) shares	Nov. 08, 2017 USD ($) $ / shares shares	Jul. 31, 2019 shares	Dec. 31, 2019 USD ($) vote $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Jun. 30, 2019 shares	Dec. 31, 2016 shares
Class of Stock [Line Items]
Number of votes to which holders of common shares are entitled for each share held | vote								1
Preferred stock, votes per share (in vote) | vote								1
Dividend rate (usd per share) | $ / shares								$ 0.16
Cash paid for preferred stock dividends declared (in usd per share) | $ / shares								$ 0.16	$ 0.16
Proceeds from sale of common stock included in accounts receivable | $								$ 2,848,000	$ 0		$ 0
Noncumulative Dividend Percentage1								10.00%
Temporary Equity, Liquidation Preference Per Share | $ / shares								$ 0.10
Proceeds From Issuance Security Token Offering, Net Of Withdrawals | $										$ 104,800,000
Withdrawal Under Security Token Offering | $										22,000,000
Capitalized Offering Costs for Security Token Offering | $									21,500,000	$ 21,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares				1,250,000	2,472,188	3,722,188
Proceeds from Warrant Exercises | $				$ 50,600,000	$ 100,000,000
Proceeds from Issuance of Warrants | $						$ 6,500,000		$ 0	$ 50,588,000		$ 106,462,000
Stock And Warrants Issued During Period, Warrants, Price Per Warrant | $ / shares						$ 40.45
Series A, issued and outstanding - 0 and 127
Class of Stock [Line Items]
Preferred stock, shares outstanding | shares								0	127,000	127,000
Series A-1, issued and outstanding - 4,210 and 0 (including 4,085 shares declared as a stock dividend, not yet distributed)
Class of Stock [Line Items]
Shares issued upon conversion (in shares) | shares								1
Preferred stock, shares outstanding | shares								4,210,000	0	0
At-The-Market Agreement [Member] | JonesTrading Institutional Services LLC [Member]
Class of Stock [Line Items]
Sale of Stock, Number of Shares Issued in Transaction | shares								7,590,498	2,883,344
Proceeds from Issuance or Sale of Equity | $								$ 85,800,000	$ 94,600,000
Deferred Offering Costs | $								2,000,000	$ 2,600,000	$ 2,600,000
tZero.com, Inc. [Member]
Class of Stock [Line Items]
Sale of Stock, Number of Shares Issued in Transaction | shares		508,710
Sale Of Stock, Number of Shares Issued In Transaction As A Percentage Of Total Shares Issued And Outstanding		0.50%
Sale Of Stock, Total Consideration Received On Transaction | $		$ 5,000,000
Sale of Stock, Consideration Received on Transaction | $								911,000
tZero.com, Inc. [Member] | GSR Capital [Member]
Class of Stock [Line Items]
Payments to Acquire Equity Method Investments | $			$ 30,000,000
Sale Of Tokens, Price Per Token | $ / shares			$ 6.67
Sale of Stock, Consideration Received on Transaction | $								$ 4,400,000
Preferred Stock [Member] | Series A, issued and outstanding - 0 and 127
Class of Stock [Line Items]
Partners' Capital Account, Units, Converted | shares								2,000	0		0
Preferred stock, shares outstanding | shares								0	127,000	127,000	127,000	2,895	127,000
Preferred Stock [Member] | Series A-1, issued and outstanding - 4,210 and 0 (including 4,085 shares declared as a stock dividend, not yet distributed)
Class of Stock [Line Items]
Partners' Capital Account, Units, Converted | shares	122,526
Preferred stock, shares outstanding | shares								4,210,000	0	0	0		0
Preferred Stock [Member] | Series A Preferred Stock Exchange [Member] | Series A, issued and outstanding - 0 and 127
Class of Stock [Line Items]
Partners' Capital Account, Units, Converted | shares	122,526						2,020
Preferred Stock [Member] | Series A Preferred Stock Conversion [Member] | Series A, issued and outstanding - 0 and 127
Class of Stock [Line Items]
Partners' Capital Account, Units, Converted | shares	1,144						875