Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 01, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 109,572	$ 106,582
Short-term investments	337,629	297,961
Accounts receivable, less reserves of $1,664 and $1,568 in 2018 and 2017, respectively	96,649	119,388
Unbilled revenue	4,232	7,454
Inventories	96,399	67,923
Prepaid expenses and other current assets	26,068	30,683
Total current assets	670,549	629,991
Long-term investments	356,181	423,441
Property, plant, and equipment, net	85,205	78,048
Goodwill	113,208	113,208
Intangible assets, net	12,420	13,189
Deferred income taxes	29,135	27,385
Other assets	2,217	2,491
Total assets	1,268,915	1,287,753
Current liabilities:
Accounts payable	29,136	23,463
Accrued expenses	56,463	68,249
Accrued income taxes	11,915	11,503
Deferred revenue and customer deposits	15,504	9,420
Total current liabilities	113,018	112,635
Deferred income taxes	319	312
Reserve for income taxes	6,958	6,488
Accrued income taxes	66,741	66,741
Other non-current liabilities	4,780	5,904
Total liabilities	191,816	192,080
Shareholders’ equity:
Common stock, $.002 par value – Authorized: 200,000 shares in 2018 and 2017, respectively, issued and outstanding: 172,948 and 173,507 shares in 2018 and 2017, respectively	346	347
Additional paid-in capital	485,654	461,338
Retained earnings	622,856	668,587
Accumulated other comprehensive loss, net of tax	(31,757)	(34,599)
Total shareholders’ equity	1,077,099	1,095,673
Total liabilities and shareholders' equity	$ 1,268,915	$ 1,287,753