FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Level 1
Assets, Fair Value Disclosure [Abstract]
Assets –cash & cash equivalents	$ 69,935	$ 105,027
Assets –restricted cash	2,768	2,767
Total Assets	72,703	107,795
Liabilities:
Forward purchase option derivative	0	0
Earnout liability	0	0
Total Liabilities	13,841	15,396
Level 1 | Public Warrants
Liabilities:
Warrant liabilities	13,841
Level 1 | Private Warrants
Liabilities:
Warrant liabilities	0
Level 1 | Common stock warrants
Liabilities:
Warrant liabilities		15,396
Level 1 | Preferred stock warrants
Liabilities:
Warrant liabilities		0
Level 2
Assets, Fair Value Disclosure [Abstract]
Assets –cash & cash equivalents	0	0
Assets –restricted cash	0	0
Total Assets	0	0
Liabilities:
Forward purchase option derivative	0	0
Earnout liability	0	0
Total Liabilities	5,979	6,649
Level 2 | Public Warrants
Liabilities:
Warrant liabilities	0
Level 2 | Private Warrants
Liabilities:
Warrant liabilities	5,979
Level 2 | Common stock warrants
Liabilities:
Warrant liabilities		0
Level 2 | Preferred stock warrants
Liabilities:
Warrant liabilities		6,649
Level 3
Assets, Fair Value Disclosure [Abstract]
Assets –cash & cash equivalents	0	0
Assets –restricted cash	0	0
Total Assets	0	0
Liabilities:
Forward purchase option derivative	17,609	4,203
Earnout liability	20,145	27,134
Total Liabilities	37,754	31,337
Level 3 | Public Warrants
Liabilities:
Warrant liabilities	0
Level 3 | Private Warrants
Liabilities:
Warrant liabilities	$ 0
Level 3 | Common stock warrants
Liabilities:
Warrant liabilities		0
Level 3 | Preferred stock warrants
Liabilities:
Warrant liabilities		$ 0