Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 135,682	$ 139,359
Short-term investments	29,072	38,513
Accounts receivable, net of allowances of $3,752 and $3,404, respectively	19,908	19,071
Prepaid expenses and other current assets	9,091	14,311
Deferred income taxes	2,203	1,643
Total current assets	195,956	212,897
Long-term investments	28,593	43,077
Property and equipment, net	14,205	14,438
Tradenames, net	34,881	34,691
Patent and patent licenses, net	17,411	17,517
Customer relationships, net	41,819	35,865
Goodwill	290,097	279,016
Other purchased intangibles, net	9,630	9,994
Deferred income taxes	4,690	3,160
Other assets	652	516
Total assets	637,934	651,171
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	23,224	24,070
Income taxes payable	2,372	1,494
Deferred revenue	28,157	26,695
Liability for uncertain tax positions	5,523	5,523
Deferred income taxes	3	16
Total current liabilities	59,279	57,798
Liability for uncertain tax positions	26,089	24,554
Deferred income taxes	10,154	12,102
Other long-term liabilities	2,175	2,342
Total liabilities	97,697	96,796
Commitments and contingencies	0	0
Preferred stock, $0.01 par value. Authorized 1,000,000 and none issued	0	0
Common stock, $0.01 par value. Authorized 95,000,000 at March 31, 2012 and December 31, 2011; total issued 54,301,815 and 55,389,636 shares at March 31, 2012 and December 31, 2011, respectively; and total outstanding 45,621,247 and 46,709,068 shares at March 31, 2012 and December 31, 2011, respectively	543	554
Additional paid-in capital	196,012	197,374
Treasury stock, at cost (8,680,568 shares at March 31, 2012 and December 31, 2011)	(112,671)	(112,671)
Retained earnings	457,458	472,595
Accumulated other comprehensive loss	(1,105)	(3,477)
Total stockholders' equity	540,237	554,375
Total liabilities and stockholders' equity	$ 637,934	$ 651,171