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STOCKHOLDERS' EQUITY - Stock grant agreements with non-employees (Details) - SADA License Agreement - Researchers, Employees of MSK	1 Months Ended		6 Months Ended	27 Months Ended
	Jul. 31, 2020 USD ($) individual	Apr. 30, 2020 USD ($) individual shares	Jun. 30, 2022 USD ($) individual	Jun. 30, 2022 USD ($)
Share-Based Compensation Awards
Number of individuals \| individual	2
Notes receivable, noncurrent	$ 2,610,000
Notes receivable term	3 years
Notes receivable interest rate (as a percent)	1.00%
Nonemployees
Share-Based Compensation Awards
Number of individuals \| individual		2	2
Vesting (as a percent)		40.00%	20.00%	80.00%
Remaining vesting percentage		60.00%	20.00%	20.00%
Nonemployees \| Research and development expense
Share-Based Compensation Awards
Non-cash expense in connection with equity issuance to non-employees		$ 7,376,000
Unrecognized compensation			$ 0	$ 0
Nonemployees \| Tranche two
Share-Based Compensation Awards
Vesting period		3 years
Common Stock \| Nonemployees
Share-Based Compensation Awards
Shares agreed to be issued \| shares		213,996
Issuance of common stock to non-employees (in shares) \| shares		213,996