Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 242,688	$ 269,073
Current investments, amortized cost of $142,469 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	143,233	103,240
Accounts receivable, allowance for credit losses of $798 and $831 in 2021 and 2020, respectively	128,822	125,696
Unbilled revenue	1,663	5,632
Inventories	61,392	60,830
Prepaid expenses and other current assets	47,773	37,220
Total current assets	625,571	601,691
Non-current investments, amortized cost of $487,978 and $390,417 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	490,363	395,125
Property, plant, and equipment, net	77,081	79,173
Operating lease assets	20,784	22,582
Goodwill	243,036	244,078
Intangible assets, net	14,628	15,555
Deferred income taxes	429,801	434,704
Other assets	7,692	7,794
Total assets	1,908,956	1,800,702
Current liabilities:
Accounts payable	20,970	16,270
Accrued expenses	60,422	77,264
Accrued income taxes	18,823	9,379
Deferred revenue and customer deposits	51,660	21,274
Operating lease liabilities	7,805	8,110
Total current liabilities	159,680	132,297
Non-current operating lease liabilities	16,223	18,120
Deferred income taxes	310,884	314,952
Reserve for income taxes	14,752	14,257
Non-current accrued income taxes	40,963	48,915
Other liabilities	9,453	9,959
Total liabilities	551,955	538,500
Shareholders’ equity:
Preferred stock, $.01 par value – Authorized: 400 shares in 2021 and 2020, respectively, no shares issued and outstanding	0	0
Common stock, $.002 par value – Authorized: 300,000 shares in 2021 and 2020, respectively, issued and outstanding: 176,608 and 175,790 shares in 2021 and 2020, respectively	353	352
Additional paid-in capital	854,491	807,739
Retained earnings	540,686	487,912
Accumulated other comprehensive loss, net of tax	(38,529)	(33,801)
Total shareholders’ equity	1,357,001	1,262,202
Total liabilities and shareholders' equity	$ 1,908,956	$ 1,800,702