Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 105,296	$ 108,212
Current investments	441,337	427,348
Accounts receivable, less reserves of $1,567 and $1,646 in 2019 and 2018, respectively	106,424	119,172
Unbilled revenue	10,202	8,312
Inventories	79,208	83,282
Prepaid expenses and other current assets	30,778	34,000
Total current assets	773,245	780,326
Non-current investments	317,054	262,039
Property, plant, and equipment, net	91,273	91,396
Operating Lease, Right-of-Use Asset	17,354	0
Goodwill	113,208	113,208
Intangible assets, net	9,344	10,113
Deferred income taxes	28,596	28,660
Other assets	3,698	3,925
Total assets	1,353,772	1,289,667
Current liabilities:
Accounts payable	20,529	16,230
Accrued expenses	48,948	60,220
Accrued income taxes	1,560	5,062
Deferred revenue and customer deposits	16,625	9,845
Operating Lease, Liability, Current	5,383	0
Total current liabilities	93,045	91,357
Operating Lease, Liability, Noncurrent	11,953	0
Deferred income taxes	0	962
Reserve for income taxes	7,748	7,106
Non-current accrued income taxes	51,113	51,113
Other liabilities	1,054	3,866
Total liabilities	164,913	154,404
Preferred Stock, Value, Outstanding	0	0
Shareholders’ equity:
Common stock, $.002 par value – Authorized: 300,000 shares in 2019 and 2018, respectively, issued and outstanding: 171,537 and 170,820 shares in 2019 and 2018, respectively	343	342
Additional paid-in capital	555,834	529,208
Retained earnings	670,754	646,214
Accumulated other comprehensive loss, net of tax	(38,072)	(40,501)
Total shareholders’ equity	1,188,859	1,135,263
Total liabilities and shareholders' equity	$ 1,353,772	$ 1,289,667