REDEEMABLE PREFERRED STOCK -Preferred Stock in Permanent Equity (Details) - USD ($) $ in Thousands	3 Months Ended		54 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Beginning balance	$ 278,114	$ 278,195
Reclassification of Series A Preferred Stock from temporary equity to permanent equity	8,243	6,948	$ 108,700
Ending balance	$ 278,515	$ 279,539	$ 278,515
Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Beginning balance (in shares)	9,784,067	8,224,254
Beginning balance	$ 262,036	$ 223,467
Ending balance (in shares)	10,125,641	8,532,056	10,125,641
Ending balance	$ 270,546	$ 231,144	$ 270,546
Series A Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Reclassification of Series A Preferred Stock from temporary equity to permanent equity	8,243	6,948
Redemption of Series A Preferred Stock	$ (685)	$ (66)
Series A Preferred Stock | Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Beginning balance (in shares)	4,377,762	2,837,094
Beginning balance	$ 108,729	$ 70,633
Reclassification of Series A Preferred Stock to permanent equity (in shares)	366,991	304,274
Reclassification of Series A Preferred Stock from temporary equity to permanent equity	$ 9,144	$ 7,588
Redemption of Series A Preferred Stock (in shares)	(29,462)	(2,452)
Redemption of Series A Preferred Stock	$ (733)	$ (61)
Ending balance (in shares)	4,715,291	3,138,916	4,715,291
Ending balance	$ 117,140	$ 78,160	$ 117,140
Series D Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Issuance of Series D Preferred Stock	$ 96	$ 145
Series D Preferred Stock | Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Beginning balance (in shares)	19,145	0
Beginning balance	$ 473	$ 0
Issuance of Series D Preferred Stock (in shares)	4,045	5,980
Issuance of Series D Preferred Stock	$ 99	$ 150
Ending balance (in shares)	23,190	5,980	23,190
Ending balance	$ 572	$ 150	$ 572
Series L Preferred Stock | Preferred Stock
Increase (Decrease) in Preferred Stock In Permanent Equity [Roll Forward]
Beginning balance (in shares)	5,387,160	5,387,160
Beginning balance	$ 152,834	$ 152,834
Ending balance (in shares)	5,387,160	5,387,160	5,387,160
Ending balance	$ 152,834	$ 152,834	$ 152,834