CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 343,472	$ 398,946
Trade receivables, net	118,640	107,626
Unbilled receivables	129,310	140,534
Inventories, net	197,035	205,062
Prepaids and other current assets	37,834	28,321
Total current assets	826,291	880,489
Operating lease right of use assets	5,047	5,144
Property, plant and equipment, net	244,495	258,497
Deferred income taxes	17,879	8,936
Goodwill		7,947
Intangible assets	31,204	32,245
Other assets	11,194	13,307
Total assets	1,136,110	1,206,565
Current liabilities:
Accounts payable	49,817	46,324
Accrued income taxes	6,943	4,561
Contract liabilities	6,431	6,901
Accrued compensation	6,916	13,599
Operating lease liabilities	1,213	1,314
Other accrued liabilities	22,126	24,241
Total current liabilities	93,446	96,940
Deferred income taxes	3,495	4,150
Income tax payable	8,988	8,868
Operating lease liabilities, long-term	3,809	3,801
Other long-term liabilities	2,171	2,105
Total liabilities	111,909	115,864
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, 35,060,690 and 35,859,540 shares issued and outstanding at March 31, 2020 and December 31, 2019	363	371
Additional paid-in capital	56,045	52,870
Retained earnings	1,136,335	1,181,023
Accumulated other comprehensive losses	(168,542)	(143,563)
Total stockholders' equity	1,024,201	1,090,701
Total liabilities and stockholders' equity	$ 1,136,110	$ 1,206,565