CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 542,914	$ 630,012
Short-term investments	190,540	99,996
Accounts receivable	99,629	82,261
Inventory	104,653	91,591
Other current assets	55,156	20,746
Total current assets	992,892	924,606
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $81,721 and $72,493	113,187	102,113
ACQUIRED TECHNOLOGY, net of accumulated amortization of $163,343 and $153,050	59,960	70,253
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $6,848 and $6,155	10,386	10,685
GOODWILL	15,535	15,535
INVESTMENTS	8,500	5,000
DEFERRED INCOME TAXES	35,579	37,695
OTHER ASSETS	114,676	103,341
TOTAL ASSETS	1,350,715	1,269,228
CURRENT LIABILITIES:
Accounts payable	10,334	13,801
Accrued expenses	27,247	41,404
Deferred revenue	122,978	105,215
Other current liabilities	2,004	4,540
Total current liabilities	162,563	164,960
DEFERRED REVENUE	46,174	57,086
RETIREMENT PLAN BENEFIT LIABILITY	79,966	78,527
OTHER LIABILITIES	70,396	55,941
Total liabilities	359,099	356,514
COMMITMENTS AND CONTINGENCIES (Note 15)
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, 49,054,059 and 49,013,476 shares issued, and 47,688,411 and 47,647,828 shares outstanding, at June 30, 2021 and December 31, 2020, respectively	491	490
Additional paid-in capital	638,991	635,595
Retained earnings	427,188	353,930
Accumulated other comprehensive loss	(33,772)	(36,019)
Treasury stock, at cost (1,365,648 shares at June 30, 2021 and December 31, 2020)	(41,284)	(41,284)
Total shareholders’ equity	991,616	912,714
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 1,350,715	$ 1,269,228