CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Cash flows from operating activities
Net loss	$ (8,878)	$ (15,417)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	3,273	4,099
Provision for severance benefits	1,514	1,405
Loss (gain) on foreign currency, net	(35)	10,226
Provision (reversal) for inventory reserves	1,208	(947)
Stock-based compensation	1,030	900
Deferred income taxes	(415)	1,313
Others, net	225	263
Changes in operating assets and liabilities
Accounts receivable, net	635	1,401
Inventories	(3,259)	801
Other receivables	(811)	(385)
Prepaid expenses	1,233	905
Other current assets	970	331
Accounts payable	2,542	563
Other accounts payable	(2,622)	(5,256)
Accrued expenses	(111)	(2,045)
Accrued income taxes	(6)	167
Other current liabilities	(901)	(387)
Other non-current liabilities	354	(624)
Payment of severance benefits	(325)	(884)
Others, net	(290)	(401)
Net cash used in operating activities	(4,669)	(3,972)
Cash flows from investing activities
Purchase of property, plant and equipment	(208)	(668)
Payment for intellectual property registration	(63)	(60)
Collection of guarantee deposits	21	1,133
Payment of guarantee deposits	(139)	(1,874)
Others, net	0	1
Net cash used in investing activities	(389)	(1,468)
Cash flows from financing activities
Proceeds from long-term borrowing	0	30,059
Acquisition of treasury stock	(1,306)	(4,659)
Repayment of financing related to water treatment facility arrangement	(111)	(121)
Repayment of principal portion of finance lease liabilities	(38)	(35)
Net cash provided by (used in) financing activities	(1,455)	25,244
Effect of exchange rates on cash and cash equivalents	557	(6,294)
Net increase (decrease) in cash and cash equivalents	(5,956)	13,510
Cash and cash equivalents at beginning of period	138,610	158,092
Cash and cash equivalents at end of period	132,654	171,602
Supplemental cash flow information
Cash paid for interest on long-term borrowing	321	0
Cash paid (refund) for income taxes	(337)	270
Non-cash investing activities
Property, plant and equipment additions in other accounts payable	1,840	285
Non-cash financing activities
Unsettled common stock repurchases	$ 247	$ 0