SHARE-BASED COMPENSATION - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Feb. 28, 2024 shares	Apr. 06, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	30,946,677
Shares issued during the period (in shares)	15,261	7,549
Number of common stock issued per vesting RSU (in shares)	1
Number of common stock issued per CSR (in shares)				1.2082
Effective exchange ratio of Foamix ordinary shares into Menlo common stock				1.8006
Weighted average remaining contractual term of outstanding options	8 years 10 months 6 days
Weighted average remaining contractual term of exercisable options	5 years 8 months 26 days
Unrecognized share based compensation expense, options | $	$ 2,300,000
Aggregate intrinsic value of options outstanding | $	0
Aggregate intrinsic value of exercisable options | $	$ 0
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	460,979
Fair value of options and RSUs granted | $	$ 2,400,000	$ 800,000
Share-based payment cost not yet recognized, weighted average period of recognition (in years)	3 years 10 months 17 days
Share-based payment cost, RSUs outstanding, weighted average period or recognition (in years)	2 years 1 month 28 days
Unrecognized share-based compensation cost | $	$ 2,300,000
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment cost not yet recognized, weighted average period of recognition (in years)	3 years 1 month 17 days
Employees and consultants | Foamix
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental compensation costs incurred | $	$ 46,000	$ 200,000
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	744,537
2023 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	1,129,856
2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	0
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	0
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	101,202
Percentage of fair market value used as purchase price	85.00%
Percent of annual earnings that may be used to purchase shares	15.00%
2024 Inducement Plan | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			500,000