CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 362,213	$ 345,955
Trade receivables, net	103,803	116,202
Unbilled receivables	139,516	140,318
Inventories, net	194,911	212,536
Prepaids and other current assets	44,278	48,182
Total current assets	844,721	863,193
Operating lease right of use assets	5,646	6,962
Property, plant and equipment, net	231,385	234,823
Deferred income taxes	6,109	5,768
Intangible assets	28,743	29,434
Other assets	10,227	10,992
Total assets	1,126,831	1,151,172
Current liabilities:
Accounts payable	38,495	37,424
Accrued income taxes	5,207	4,343
Contract liabilities	13,858	11,339
Accrued compensation	7,012	5,015
Operating lease liabilities	788	1,110
Other accrued liabilities	29,947	26,281
Total current liabilities	95,307	85,512
Deferred income taxes	6,934	6,779
Income tax payable	9,423	9,383
Operating lease liabilities, long-term	4,916	5,845
Other long-term liabilities	1,985	2,125
Total liabilities	118,565	109,644
Contingencies (Note 12)
Stockholders' equity:
Preferred stock: 10,000,000 shares authorized at $0.01 par value (none issued)
Common stock:
100,000,000 shares authorized at $0.01 par value, 35,428,778 and 35,417,712 shares issued and outstanding at March 31, 2021 and December 31, 2020	363	363
Additional paid-in capital	68,799	65,613
Retained earnings	1,090,905	1,125,263
Accumulated other comprehensive losses	(151,801)	(149,711)
Total stockholders' equity	1,008,266	1,041,528
Total liabilities and stockholders' equity	$ 1,126,831	$ 1,151,172