CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 96,117	$ 139,365
Short-term investments	228,861	188,644
Accounts receivable	36,321	24,994
Inventory	16,668	17,314
Deferred income taxes		8,661
Other current assets	5,775	6,392
Total current assets	383,742	385,370
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $33,377 and $32,167	28,552	27,203
ACQUIRED TECHNOLOGY, net of accumulated amortization of $75,864 and $70,714	146,977	152,127
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $957 and $615	15,883	16,225
GOODWILL	15,535	15,535
INVESTMENTS	14,789	14,960
DEFERRED INCOME TAXES	49,750	15,832
OTHER ASSETS	215	307
TOTAL ASSETS	655,443	627,559
CURRENT LIABILITIES:
Accounts payable	11,147	8,112
Accrued expenses	9,977	19,845
Deferred revenue	10,064	10,282
Other current liabilities	2,042	1,967
Total current liabilities	33,230	40,206
DEFERRED REVENUE	28,956	31,322
RETIREMENT PLAN BENEFIT LIABILITY	28,106	27,563
Total liabilities	90,292	99,091
COMMITMENTS AND CONTINGENCIES (Note 14)
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, 100,000,000 shares authorized, 48,364,895 and 48,270,990 shares issued, and 47,007,032 and 46,913,127 shares outstanding, at March 31, 2017 and December 31, 2016, respectively	484	483
Additional paid-in capital	605,331	604,364
Retained earnings	9,844	(25,557)
Accumulated other comprehensive loss	(10,352)	(10,666)
Treasury stock, at cost (1,357,863 shares at March 31, 2017 and December 31, 2016)	(40,158)	(40,158)
Total shareholders’ equity	565,151	528,468
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 655,443	$ 627,559