STOCK-BASED COMPENSATION - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2022 USD ($) $ / shares shares	Sep. 30, 2021 shares	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares	Dec. 31, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares) | shares			39,430,043		39,430,043		33,769,619
Weighted-average fair value of options granted (in dollars per share) | $ / shares			$ 2.26	$ 4.12	$ 2.73	$ 3.69
Option repricing ratio	1
Stock-based compensation, exercise price (in dollars per share) | $ / shares	$ 4.39
Incremental stock-based compensation expense	$ 1,600
Stock-based compensation expense, vested stock options	100
Stock-based compensation expense, nonvested stock options	$ 1,500
Stock-based compensation expense			$ 4,589	$ 2,241	$ 8,150	$ 3,926
Unrecognized compensation cost related to unvested share-based compensation arrangements granted			24,800		24,800
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, exercise price (in dollars per share) | $ / shares	$ 4.70
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, exercise price (in dollars per share) | $ / shares	$ 14.45
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted (in shares) | shares	800,000
Total grant date fair value					4,000
Stock-based compensation expense			200	$ 0	200	$ 0
Unrecognized compensation costs			$ 25,400		$ 25,400
Unrecognized compensation cost, period for recognition					2 years 10 months 24 days
RSUs | Tranche 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Aggregate fair value of equity instruments vested during the period					$ 1,300
RSUs | Tranche 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	2 years
Aggregate fair value of equity instruments vested during the period					1,400
RSUs | Tranche 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Aggregate fair value of equity instruments vested during the period					$ 1,400
RSUs | New Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					4 years
Award cliff vesting period					1 year
RSUs | Existing Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					3 years
RSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	0.00%
RSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	150.00%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition					2 years 5 months 23 days
2021 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, period for increase in shares		10 years
Percent of outstanding shares		4.00%
2021 Equity Incentive Plan | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares) | shares		21,062,853
Stock-based compensation, maximum number of shares available for issue on the exercise of incentive stock options (in shares) | shares		100,000,000
2021 Employee Stock Purchase Plan | 2021 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, period for increase in shares		10 years
Percent of outstanding shares		1.00%
Stock-based compensation, number of additional shares allowable under the plan (in shares) | shares		2,850,000
Stock-based compensation, purchase period		6 months
2021 Employee Stock Purchase Plan | Class A Common Stock | 2021 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares) | shares		4,402,757
Stock-based compensation, discount percentage from market price, beginning of period		85.00%