SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Net Loss per Share (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive securities excluded from calculation of net loss per share	20,436,601	16,673,579
Stock option
Antidilutive securities excluded from calculation of net loss per share	14,859,674	12,537,858
Employee Stock Purchase Plan
Antidilutive securities excluded from calculation of net loss per share	182,986	36,263
Restricted stock units
Antidilutive securities excluded from calculation of net loss per share	2,454,783	1,160,300
Series A Convertible Preferred Stock
Antidilutive securities excluded from calculation of net loss per share	97,000	97,000
Series B Convertible Preferred Stock
Antidilutive securities excluded from calculation of net loss per share	2,842,158	2,842,158