CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 535,157	$ 630,012
Short-term investments	253,786	99,996
Accounts receivable	96,235	82,261
Inventory	121,485	91,591
Other current assets	48,476	20,746
Total current assets	1,055,139	924,606
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $86,962 and $72,493	118,988	102,113
ACQUIRED TECHNOLOGY, net of accumulated amortization of $168,489 and $153,050	54,814	70,253
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $7,206 and $6,155	10,028	10,685
GOODWILL	15,535	15,535
INVESTMENTS	8,500	5,000
DEFERRED INCOME TAXES	32,476	37,695
OTHER ASSETS	133,111	103,341
TOTAL ASSETS	1,428,591	1,269,228
CURRENT LIABILITIES:
Accounts payable	10,939	13,801
Accrued expenses	42,736	41,404
Deferred revenue	123,475	105,215
Other current liabilities	3,111	4,540
Total current liabilities	180,261	164,960
DEFERRED REVENUE	43,458	57,086
RETIREMENT PLAN BENEFIT LIABILITY	80,676	78,527
OTHER LIABILITIES	87,874	55,941
Total liabilities	392,269	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, 49,060,909 and 49,013,476 shares issued, and 47,695,261 and 47,647,828 shares outstanding, at September 30, 2021 and December 31, 2020, respectively	491	490
Additional paid-in capital	646,049	635,595
Retained earnings	463,820	353,930
Accumulated other comprehensive loss	(32,756)	(36,019)
Treasury stock, at cost (1,365,648 shares at September 30, 2021 and December 31, 2020)	(41,284)	(41,284)
Total shareholders’ equity	1,036,322	912,714
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 1,428,591	$ 1,269,228