Interim Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 10,930	$ 13,709
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation	387	377
Equity-based compensation	3,688	3,540
Gain from sale of property and equipment		(10)
Realized gain, net on sale of available-for-sale marketable securities	(91)	(8)
Amortization of premiums on available-for-sale marketable securities	946	1,578
Accrued interest on bank deposits	(1,402)	(751)
Unrealized foreign exchange gain	(56)	(15)
Changes in operating assets and liabilities:
Decrease (increase) in trade receivables	(899)	1,421
Decrease in prepaid expenses and other accounts receivable	669	1,086
Increase in deferred taxes, net	(549)	(1,367)
Increase (decrease) in trade payables	448	(24)
Increase (decrease) in deferred revenues	(207)	834
Decrease in accrued expenses and other payables	(1,567)	(1,842)
Increase in income taxes payable	1,165	532
Excess tax benefit from equity-based compensation	(710)	(1,223)
Increase (Decrease) in accrued severance pay, net	(65)	205
Net cash provided by operating activities	12,687	18,042
Cash flows from investing activities:
Purchase of property and equipment	(344)	(221)
Proceeds from sale of property and equipment		10
Investment in bank deposits	(34,604)	(25,500)
Proceeds from bank deposits	34,353	13,198
Investment in available-for-sale marketable securities	(32,867)	(34,392)
Proceeds from maturity of available-for-sale marketable securities	12,330	21,089
Proceeds from sale of available-for-sale marketable securities	38,159	4,398
Investment in other companies	(1,533)
Net cash provided by (used in) investing activities	15,494	(21,418)
Cash flows from financing activities:
Purchase of Treasury Stock	(23,652)
Proceeds from issuance of Common Stock upon exercise of stock options	166	6,419
Proceeds from issuance of Common Stock under employee stock purchase plan	629	1,236
Proceeds from issuance of Treasury Stock upon exercise of stock options	111
Proceeds from issuance of Treasury Stock under employee stock purchase plan	620
Excess tax benefit from equity-based compensation	710	1,223
Net cash provided by (used in) financing activities	(21,416)	8,878
Effect of exchange rate movements on cash	(39)	95
Increase in cash and cash equivalents	6,726	5,597
Cash and cash equivalents at the beginning of the period	14,954	17,098
Cash and cash equivalents at the end of the period	$ 21,680	$ 22,695