Condensed Consolidated Balance Sheets (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 97,524	$ 126,363
Short-term investments, available for sale	105,389	103,300
Accounts receivable, net of allowances of $11.5 and $13.2 million, respectively	91,546	85,453
Inventories	47,271	46,216
Other current assets	38,943	24,317
Total current assets	380,673	385,649
Property and equipment, net	29,950	26,547
Restricted investments	56,850	56,850
Goodwill	156,002	139,517
Intangible assets, net	52,966	49,140
Deferred tax assets	41,845	47,137
Other assets	1,756	1,741
Total assets	720,042	706,581
Liabilities and Stockholders' Equity
Accounts payable	44,059	49,189
Accrued and other liabilities	49,957	45,730
Deferred revenue	33,496	24,298
Income taxes payable	2,070	1,182
Total current liabilities	129,582	120,399
Contingent liabilities	2,111	619
Deferred tax liabilities	2,797	1,292
Noncurrent income taxes payable	37,122	32,522
Total liabilities	171,612	154,832
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock, $0.01 par value; 5,000 shares authorized; none issued and outstanding
Common stock, $0.01 par value; 150,000 shares authorized; 76,420 and 74,456 shares issued and outstanding, respectively	764	745
Additional paid-in capital	719,855	692,904
Treasury stock, at cost, 30,909 and 28,031 shares, respectively	(533,614)	(488,559)
Accumulated other comprehensive income	1,732	2,955
Retained earnings	359,693	343,704
Total stockholders' equity	548,430	551,749
Total liabilities and stockholders' equity	$ 720,042	$ 706,581