DISCLOSURES ABOUT FAIR VALUE OF FINANCIAL INSTRUMENTS - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Jan. 04, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for private warrants	$ 12,850	$ 18,893	$ 15,836	$ 18,893	$ 12,850	$ 13,614	$ 0
Gain on fair value of private warrant liability	$ 6,042	$ (3,056)	$ 15,003	$ 11,947	$ 17,989	17,225	0
Carrying Amount | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents						25,704	2,989
Accounts receivable, net						9,161	10,033
Liability for private warrants						13,614
Borrowings from Partner Bank						0	21,000
Estimated Fair Value | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents						25,704	2,989
Accounts receivable, net						9,161	10,033
Liability for private warrants						13,614		$ 30,800
Borrowings from Partner Bank							21,000
Estimated Fair Value | Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents						25,704	2,989
Accounts receivable, net						9,161	10,033
Liability for private warrants						0
Borrowings from Partner Bank							0
Estimated Fair Value | Fair Value, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents						0	0
Accounts receivable, net						0	0
Liability for private warrants						0
Borrowings from Partner Bank							21,000
Estimated Fair Value | Fair Value, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents						0	0
Accounts receivable, net						0	0
Liability for private warrants						$ 13,614
Borrowings from Partner Bank							$ 0