Consolidated Balance Sheets - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Current assets    
Cash and cash equivalents $ 131,682 $ 128,575
Accounts receivable, net 85,570 92,026
Unbilled accounts receivable 35,857  
Inventories, net 57,456 73,073
Other receivables 8,468 4,292
Prepaid expenses 10,227 9,250
Hedge collateral (Note 7) 10,100 7,600
Other current assets (Notes 7 and 18) 11,023 15,444
Total current assets 350,383 330,260
Property, plant and equipment, net 197,034 205,903
Intangible assets, net 3,966 4,061
Long-term prepaid expenses 13,858 12,791
Other non-current assets 5,851 5,774
Total assets 571,092 558,789
Current liabilities    
Accounts payable 60,742 65,940
Other accounts payable 11,123 10,261
Accrued expenses 49,506 51,746
Deferred revenue 13,440 8,335
Other current liabilities (Note 7) 5,149 1,860
Total current liabilities 139,960 138,142
Long-term borrowings, net 304,489 303,416
Accrued severance benefits, net 145,542 148,905
Other non-current liabilities (Note 4) 14,894 7,963
Total liabilities 604,885 598,426
Commitments and contingencies (Note 18)
Stockholders' equity    
Common stock, $0.01 par value, 150,000,000 shares authorized, 42,877,395 shares issued and 34,483,754 outstanding at June 30, 2018 and 42,563,808 shares issued and 34,189,599 outstanding at December 31, 2017 429 426
Additional paid-in capital 139,502 136,259
Accumulated deficit (51,147) (40,889)
Treasury stock, 8,393,641shares at June 30, 2018 and 8,374,209 shares at December 31, 2017 (102,518) (102,319)
Accumulated other comprehensive loss (20,059) (33,114)
Total stockholders' deficit (33,793) (39,637)
Total liabilities and stockholders' equity $ 571,092 $ 558,789