CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 212,085	$ 225,477
Accounts receivable, net	32,143	35,380
Inventories, net	36,360	39,883
Other receivables	5,342	7,847
Prepaid expenses	11,238	10,560
Hedge collateral (Note 7)	2,820	2,940
Other current assets (Note 18)	14,927	15,766
Total current assets	314,915	337,853
Property, plant and equipment, net	104,568	110,747
Operating lease right-of-use assets	5,413	5,265
Intangible assets, net	1,784	1,930
Long-term prepaid expenses	9,101	10,939
Deferred income taxes	37,380	38,324
Other non-current assets	14,683	11,587
Total assets	487,844	516,645
Current liabilities
Accounts payable	19,921	17,998
Other accounts payable	9,216	9,702
Accrued expenses (Note 6)	17,125	9,688
Accrued income taxes	146	3,154
Operating lease liabilities	1,622	1,397
Other current liabilities	5,261	5,306
Total current liabilities	53,291	47,245
Accrued severance benefits, net	23,608	23,121
Non-current operating lease liabilities	3,996	4,091
Other non-current liabilities	13,596	14,035
Total liabilities	94,491	88,492
Commitments and contingencies (Note 18)
Stockholders' equity
Common stock, $0.01 par value, 150,000,000 shares authorized, 56,437,182 shares issued and 42,589,315 outstanding at March 31, 2023 and 56,432,449 shares issued and 43,824,575 outstanding at December 31, 2022	564	564
Additional paid-in capital	267,187	266,058
Retained earnings	314,036	335,506
Treasury stock, 13,847,867 shares at March 31, 2023 and 12,607,874 shares at December 31, 2022, respectively	(173,441)	(161,422)
Accumulated other comprehensive loss	(14,993)	(12,553)
Total stockholders' equity	393,353	428,153
Total liabilities and stockholders' equity	$ 487,844	$ 516,645