CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 211,022	$ 132,840
Short-term investments	304,323	287,446
Accounts receivable	43,129	52,355
Inventory	70,000	36,265
Other current assets	6,366	10,276
Total current assets	634,840	519,182
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $44,943 and $36,368	69,739	56,450
ACQUIRED TECHNOLOGY, net of accumulated amortization of $111,890 and $91,312	110,951	131,529
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $3,384 and $2,000	13,456	14,840
GOODWILL	15,535	15,535
INVESTMENTS		14,794
DEFERRED INCOME TAXES	24,377	27,022
OTHER ASSETS	64,526	604
TOTAL ASSETS	933,424	779,956
CURRENT LIABILITIES:
Accounts payable	10,532	13,774
Accrued expenses	36,057	35,019
Deferred revenue	80,782	14,981
Other current liabilities	5,811	50
Total current liabilities	133,182	63,824
DEFERRED REVENUE	41,785	23,902
RETIREMENT PLAN BENEFIT LIABILITY	44,055	33,176
OTHER LIABILITIES	23,896
Total liabilities	242,918	120,902
COMMITMENTS AND CONTINGENCIES (Note 16)
SHAREHOLDERS' EQUITY:
Preferred Stock, par value $0.01 per share, 5,000,000 shares authorized, 200,000 shares of Series A Nonconvertible Preferred Stock issued and outstanding (liquidation value of $7.50 per share or $1,500)	2	2
Common Stock, par value $0.01 per share, 200,000,000 shares authorized, 48,681,524 and 48,476,034 shares issued, and 47,319,887 and 47,118,171 shares outstanding at December 31, 2018 and December 31, 2017, respectively	487	485
Additional paid-in capital	617,334	611,063
Retained earnings	129,552	99,126
Accumulated other comprehensive loss	(16,234)	(11,464)
Treasury stock, at cost (1,361,637 and 1,357,863 shares at December 31, 2018 and December 31, 2017)	(40,635)	(40,158)
Total shareholders’ equity	690,506	659,054
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 933,424	$ 779,956