FAIR VALUE MEASUREMENTS - Valuation of financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Foxconn warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants	$ 300
Fair Value, Inputs, Level 3 | Private warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		$ 254
Fair Value, Inputs, Level 3 | Foxconn warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		170
Fair Value, Recurring
FAIR VALUE MEASUREMENTS
Cash and Cash Equivalents	87,096	121,358
Short-term investments		100,297
Fair Value, Recurring | Private warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		254
Fair Value, Recurring | Foxconn warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		170
Fair Value, Recurring | Fair Value, Inputs, Level 1
FAIR VALUE MEASUREMENTS
Cash and Cash Equivalents	$ 87,096	121,358
Fair Value, Recurring | Fair Value, Inputs, Level 2
FAIR VALUE MEASUREMENTS
Short-term investments		100,297
Fair Value, Recurring | Fair Value, Inputs, Level 3 | Private warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		254
Fair Value, Recurring | Fair Value, Inputs, Level 3 | Foxconn warrants
FAIR VALUE MEASUREMENTS
Fair value of warrants		$ 170