CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
CURRENT ASSETS:
Cash and cash equivalents	$ 630,012	$ 131,627
Short-term investments	99,996	514,461
Accounts receivable	82,261	60,452
Inventory	91,591	63,953
Other current assets	20,746	21,946
Total current assets	924,606	792,439
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $72,493 and $57,276	102,113	87,872
ACQUIRED TECHNOLOGY, net of accumulated amortization of $153,050 and $132,468	70,253	90,774
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $6,155 and $4,768	10,685	12,072
GOODWILL	15,535	15,535
INVESTMENTS	5,000	5,000
DEFERRED INCOME TAXES	37,695	30,375
OTHER ASSETS	103,341	86,090
TOTAL ASSETS	1,269,228	1,120,157
CURRENT LIABILITIES:
Accounts payable	13,801	13,296
Accrued expenses	41,404	49,022
Deferred revenue	105,215	97,333
Other current liabilities	4,540	1,857
Total current liabilities	164,960	161,508
DEFERRED REVENUE	57,086	47,529
RETIREMENT PLAN BENEFIT LIABILITY	78,527	51,117
OTHER LIABILITIES	55,941	48,554
Total liabilities	356,514	308,708
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, 49,013,476 and 48,852,193 shares issued, and 47,647,828 and 47,486,545 shares outstanding at December 31, 2020 and December 31, 2019, respectively	490	489
Additional paid-in capital	635,595	620,236
Retained earnings	353,930	249,003
Accumulated other comprehensive loss	(36,019)	(16,997)
Treasury stock, at cost (1,365,648 shares at December 31, 2020 and December 31, 2019)	(41,284)	(41,284)
Total shareholders’ equity	912,714	811,449
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 1,269,228	$ 1,120,157