SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Convertible Equity Shares and Restricted Stock Awards Excluded from Calculation of Diluted Net Loss per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from calculation of diluted net loss per share	18,402	15,729	10,380	21,411
Restricted stock awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from calculation of diluted net loss per share	375	915	429	861
Series A convertible preferred stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from calculation of diluted net loss per share	10,840	7,002	6,022	9,703
Convertible Standard General promissory notes | Convertible Promissory Note
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from calculation of diluted net loss per share	4,693	6,198	2,543	8,610
Convertible Emmis promissory note | Convertible Promissory Note
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from calculation of diluted net loss per share	2,494	1,614	1,386	2,237