ACCOUNTING POLICIES - Computation of Basic and Diluted Net Income (Loss) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per share
Consolidated net income	$ (26,978)	$ (30,938)	$ (24,681)	$ (39,244)	$ (42,327)	$ (47,923)	$ (64,911)	$ (50,909)	$ (121,841)	$ (206,070)	$ (109,878)
Less: Preferred stock converted to common stock									0	3,098	0
Gain (Loss) On Repurchase Of Crypocurrencies									(425)	0	0
Less: Preferred stock dividends—declared and accumulated									894	77	216
Net Income (Loss) Available To Common Stockholders, Before Undistributed Earnings (Loss) Allocated To Participating Securities, Basic									(122,310)	(209,245)	(110,094)
Less: Undistributed loss allocated to participating securities									(1,665)	(4,368)	(2,960)
Net loss attributable to common shares									$ (120,645)	$ (204,877)	$ (107,134)
Net loss per common share—basic:
Net loss attributable to common shares—basic:	$ (0.73)	$ (0.89)	$ (0.69)	$ (1.18)	$ (1.39)	$ (1.55)	$ (2.20)	$ (1.74)	$ (3.46)	$ (6.83)	$ (4.28)
Weighted average common shares outstanding—basic	36,573	35,241	35,225	32,370	32,112	30,279	28,903	28,566	34,865	29,976	25,044
Effect of dilutive securities:
Stock options and restricted stock awards (in shares)									0	0	0
Weighted average common shares outstanding—diluted	36,573	35,241	35,225	32,370	32,112	30,279	28,903	28,566	34,865	29,976	25,044
Net loss attributable to common shares—diluted:	$ (0.73)	$ (0.89)	$ (0.69)	$ (1.18)	$ (1.39)	$ (1.55)	$ (2.20)	$ (1.74)	$ (3.46)	$ (6.83)	$ (4.28)
Stock options and restricted stock awards
Anti-dilutive securities excluded from computation of earnings per share
Stock options and restricted stock units (in shares)									1,051	543	226
Warrant
Anti-dilutive securities excluded from computation of earnings per share
Stock options and restricted stock units (in shares)									0	21	78